Swift 5.x, both device & simulator WITH ENUMS(to check whatever group or model you prefer)

(always checked and updated!)

with the last: iPad 10th generation, iPhone 16 ALL VERSIONS and Apple TV 4K (2nd generation) , (updates also for all iPods, Apple Watches and Apple TVs)

This method detects the correct model even if it's a simulator. (The exact name for the simulator device model running in your simulator)

With this answer you can check multiple device in few lines thanks to the enums

example:

var myDefaultFontSize: CGFloat = 26.0
switch UIDevice().type {
    case .iPhoneSE, .iPhone5, .iPhone5S: print("default value")
    case .iPhone6, .iPhone7, .iPhone8, .iPhone6S, .iPhoneX: myDefaultFontSize += 4
    default: break
}

This is the code:

public enum Model : String {

//Simulator
case simulator     = "simulator/sandbox",

//iPod
iPod1              = "iPod 1",
iPod2              = "iPod 2",
iPod3              = "iPod 3",
iPod4              = "iPod 4",
iPod5              = "iPod 5",
iPod6              = "iPod 6",
iPod7              = "iPod 7",

//iPad
iPad2              = "iPad 2",
iPad3              = "iPad 3",
iPad4              = "iPad 4",
iPadAir            = "iPad Air ",
iPadAir2           = "iPad Air 2",
iPadAir3           = "iPad Air 3",
iPadAir4           = "iPad Air 4",
iPadAir5           = "iPad Air 5",
iPad5              = "iPad 5", //iPad 2017
iPad6              = "iPad 6", //iPad 2018
iPad7              = "iPad 7", //iPad 2019
iPad8              = "iPad 8", //iPad 2020
iPad9              = "iPad 9", //iPad 2021
iPad10             = "iPad 10", //iPad 2022

//iPad Mini
iPadMini           = "iPad Mini",
iPadMini2          = "iPad Mini 2",
iPadMini3          = "iPad Mini 3",
iPadMini4          = "iPad Mini 4",
iPadMini5          = "iPad Mini 5",
iPadMini6          = "iPad Mini 6",

//iPad Pro
iPadPro9_7         = "iPad Pro 9.7\"",
iPadPro10_5        = "iPad Pro 10.5\"",
iPadPro11          = "iPad Pro 11\"",
iPadPro2_11        = "iPad Pro 11\" 2nd gen",
iPadPro3_11        = "iPad Pro 11\" 3rd gen",
iPadPro12_9        = "iPad Pro 12.9\"",
iPadPro2_12_9      = "iPad Pro 2 12.9\"",
iPadPro3_12_9      = "iPad Pro 3 12.9\"",
iPadPro4_12_9      = "iPad Pro 4 12.9\"",
iPadPro5_12_9      = "iPad Pro 5 12.9\"",

//iPhone
iPhone4            = "iPhone 4",
iPhone4S           = "iPhone 4S",
iPhone5            = "iPhone 5",
iPhone5S           = "iPhone 5S",
iPhone5C           = "iPhone 5C",
iPhone6            = "iPhone 6",
iPhone6Plus        = "iPhone 6 Plus",
iPhone6S           = "iPhone 6S",
iPhone6SPlus       = "iPhone 6S Plus",
iPhoneSE           = "iPhone SE",
iPhone7            = "iPhone 7",
iPhone7Plus        = "iPhone 7 Plus",
iPhone8            = "iPhone 8",
iPhone8Plus        = "iPhone 8 Plus",
iPhoneX            = "iPhone X",
iPhoneXS           = "iPhone XS",
iPhoneXSMax        = "iPhone XS Max",
iPhoneXR           = "iPhone XR",
iPhone11           = "iPhone 11",
iPhone11Pro        = "iPhone 11 Pro",
iPhone11ProMax     = "iPhone 11 Pro Max",
iPhoneSE2          = "iPhone SE 2nd gen",
iPhone12Mini       = "iPhone 12 Mini",
iPhone12           = "iPhone 12",
iPhone12Pro        = "iPhone 12 Pro",
iPhone12ProMax     = "iPhone 12 Pro Max",
iPhone13Mini       = "iPhone 13 Mini",
iPhone13           = "iPhone 13",
iPhone13Pro        = "iPhone 13 Pro",
iPhone13ProMax     = "iPhone 13 Pro Max",
iPhoneSE3          = "iPhone SE 3nd gen",
iPhone14           = "iPhone 14",
iPhone14Plus       = "iPhone 14 Plus",
iPhone14Pro        = "iPhone 14 Pro",
iPhone14ProMax     = "iPhone 14 Pro Max",
iPhone15           = "iPhone 15",
iPhone15Plus       = "iPhone 15 Plus",
iPhone15Pro        = "iPhone 15 Pro",
iPhone15ProMax     = "iPhone 15 Pro Max",
iPhone16           = "iPhone 16" ,
iPhone16Plus       = "iPhone 16 Plus",
iPhone16Pro        = "iPhone 16 Pro",
iPhone16ProMax     = "iPhone 16 Pro Max",
iPhone16e          = "iPhone 16e",

// Apple Watch
AppleWatch1         = "Apple Watch 1gen",
AppleWatchS1        = "Apple Watch Series 1",
AppleWatchS2        = "Apple Watch Series 2",
AppleWatchS3        = "Apple Watch Series 3",
AppleWatchS4        = "Apple Watch Series 4",
AppleWatchS5        = "Apple Watch Series 5",
AppleWatchSE        = "Apple Watch Special Edition",
AppleWatchS6        = "Apple Watch Series 6",
AppleWatchS7        = "Apple Watch Series 7",

//Apple TV
AppleTV1           = "Apple TV 1gen",
AppleTV2           = "Apple TV 2gen",
AppleTV3           = "Apple TV 3gen",
AppleTV4           = "Apple TV 4gen",
AppleTV_4K         = "Apple TV 4K",
AppleTV2_4K        = "Apple TV 4K 2gen",
AppleTV3_4K        = "Apple TV 4K 3gen",

unrecognized       = "?unrecognized?"
}

// #-#-#-#-#-#-#-#-#-#-#-#-#
// MARK: UIDevice extensions
// #-#-#-#-#-#-#-#-#-#-#-#-#

    public extension UIDevice {
    
    var type: Model {
        var systemInfo = utsname()
        uname(&systemInfo)
        let modelCode = withUnsafePointer(to: &systemInfo.machine) {
            $0.withMemoryRebound(to: CChar.self, capacity: 1) {
                ptr in String.init(validatingUTF8: ptr)
            }
        }
    
        let modelMap : [String: Model] = [
    
            //Simulator
            "i386"      : .simulator,
            "x86_64"    : .simulator,
    
            //iPod
            "iPod1,1"   : .iPod1,
            "iPod2,1"   : .iPod2,
            "iPod3,1"   : .iPod3,
            "iPod4,1"   : .iPod4,
            "iPod5,1"   : .iPod5,
            "iPod7,1"   : .iPod6,
            "iPod9,1"   : .iPod7,
    
            //iPad
            "iPad2,1"   : .iPad2,
            "iPad2,2"   : .iPad2,
            "iPad2,3"   : .iPad2,
            "iPad2,4"   : .iPad2,
            "iPad3,1"   : .iPad3,
            "iPad3,2"   : .iPad3,
            "iPad3,3"   : .iPad3,
            "iPad3,4"   : .iPad4,
            "iPad3,5"   : .iPad4,
            "iPad3,6"   : .iPad4,
            "iPad6,11"  : .iPad5, //iPad 2017
            "iPad6,12"  : .iPad5,
            "iPad7,5"   : .iPad6, //iPad 2018
            "iPad7,6"   : .iPad6,
            "iPad7,11"  : .iPad7, //iPad 2019
            "iPad7,12"  : .iPad7,
            "iPad11,6"  : .iPad8, //iPad 2020
            "iPad11,7"  : .iPad8,
            "iPad12,1"  : .iPad9, //iPad 2021
            "iPad12,2"  : .iPad9,
            "iPad13,18" : .iPad10,
            "iPad13,19" : .iPad10,
    
            //iPad Mini
            "iPad2,5"   : .iPadMini,
            "iPad2,6"   : .iPadMini,
            "iPad2,7"   : .iPadMini,
            "iPad4,4"   : .iPadMini2,
            "iPad4,5"   : .iPadMini2,
            "iPad4,6"   : .iPadMini2,
            "iPad4,7"   : .iPadMini3,
            "iPad4,8"   : .iPadMini3,
            "iPad4,9"   : .iPadMini3,
            "iPad5,1"   : .iPadMini4,
            "iPad5,2"   : .iPadMini4,
            "iPad11,1"  : .iPadMini5,
            "iPad11,2"  : .iPadMini5,
            "iPad14,1"  : .iPadMini6,
            "iPad14,2"  : .iPadMini6,
    
            //iPad Pro
            "iPad6,3"   : .iPadPro9_7,
            "iPad6,4"   : .iPadPro9_7,
            "iPad7,3"   : .iPadPro10_5,
            "iPad7,4"   : .iPadPro10_5,
            "iPad6,7"   : .iPadPro12_9,
            "iPad6,8"   : .iPadPro12_9,
            "iPad7,1"   : .iPadPro2_12_9,
            "iPad7,2"   : .iPadPro2_12_9,
            "iPad8,1"   : .iPadPro11,
            "iPad8,2"   : .iPadPro11,
            "iPad8,3"   : .iPadPro11,
            "iPad8,4"   : .iPadPro11,
            "iPad8,9"   : .iPadPro2_11,
            "iPad8,10"  : .iPadPro2_11,
            "iPad13,4"  : .iPadPro3_11,
            "iPad13,5"  : .iPadPro3_11,
            "iPad13,6"  : .iPadPro3_11,
            "iPad13,7"  : .iPadPro3_11,
            "iPad8,5"   : .iPadPro3_12_9,
            "iPad8,6"   : .iPadPro3_12_9,
            "iPad8,7"   : .iPadPro3_12_9,
            "iPad8,8"   : .iPadPro3_12_9,
            "iPad8,11"  : .iPadPro4_12_9,
            "iPad8,12"  : .iPadPro4_12_9,
            "iPad13,8"  : .iPadPro5_12_9,
            "iPad13,9"  : .iPadPro5_12_9,
            "iPad13,10" : .iPadPro5_12_9,
            "iPad13,11" : .iPadPro5_12_9,
    
            //iPad Air
            "iPad4,1"   : .iPadAir,
            "iPad4,2"   : .iPadAir,
            "iPad4,3"   : .iPadAir,
            "iPad5,3"   : .iPadAir2,
            "iPad5,4"   : .iPadAir2,
            "iPad11,3"  : .iPadAir3,
            "iPad11,4"  : .iPadAir3,
            "iPad13,1"  : .iPadAir4,
            "iPad13,2"  : .iPadAir4,
            "iPad13,16" : .iPadAir5,
            "iPad13,17" : .iPadAir5,
    
            //iPhone
            "iPhone3,1" : .iPhone4,
            "iPhone3,2" : .iPhone4,
            "iPhone3,3" : .iPhone4,
            "iPhone4,1" : .iPhone4S,
            "iPhone5,1" : .iPhone5,
            "iPhone5,2" : .iPhone5,
            "iPhone5,3" : .iPhone5C,
            "iPhone5,4" : .iPhone5C,
            "iPhone6,1" : .iPhone5S,
            "iPhone6,2" : .iPhone5S,
            "iPhone7,1" : .iPhone6Plus,
            "iPhone7,2" : .iPhone6,
            "iPhone8,1" : .iPhone6S,
            "iPhone8,2" : .iPhone6SPlus,
            "iPhone8,4" : .iPhoneSE,
            "iPhone9,1" : .iPhone7,
            "iPhone9,3" : .iPhone7,
            "iPhone9,2" : .iPhone7Plus,
            "iPhone9,4" : .iPhone7Plus,
            "iPhone10,1" : .iPhone8,
            "iPhone10,4" : .iPhone8,
            "iPhone10,2" : .iPhone8Plus,
            "iPhone10,5" : .iPhone8Plus,
            "iPhone10,3" : .iPhoneX,
            "iPhone10,6" : .iPhoneX,
            "iPhone11,2" : .iPhoneXS,
            "iPhone11,4" : .iPhoneXSMax,
            "iPhone11,6" : .iPhoneXSMax,
            "iPhone11,8" : .iPhoneXR,
            "iPhone12,1" : .iPhone11,
            "iPhone12,3" : .iPhone11Pro,
            "iPhone12,5" : .iPhone11ProMax,
            "iPhone12,8" : .iPhoneSE2,
            "iPhone13,1" : .iPhone12Mini,
            "iPhone13,2" : .iPhone12,
            "iPhone13,3" : .iPhone12Pro,
            "iPhone13,4" : .iPhone12ProMax,
            "iPhone14,4" : .iPhone13Mini,
            "iPhone14,5" : .iPhone13,
            "iPhone14,2" : .iPhone13Pro,
            "iPhone14,3" : .iPhone13ProMax,
            "iPhone14,6" : .iPhoneSE3,
            "iPhone14,7" : .iPhone14,
            "iPhone14,8" : .iPhone14Plus,
            "iPhone15,2" : .iPhone14Pro,
            "iPhone15,3" : .iPhone14ProMax,
            "iPhone15,4" : .iPhone15,
            "iPhone15,5" : .iPhone15Plus,
            "iPhone16,1" : .iPhone15Pro,
            "iPhone16,2" : .iPhone15ProMax,
            "iPhone17,3" : .iPhone16,
            "iPhone17,4" : .iPhone16Plus,
            "iPhone17,1" : .iPhone16Pro,
            "iPhone17,2" : .iPhone16ProMax,
            "iPhone17,5" : .iPhone16e,
            
            // Apple Watch
            "Watch1,1" : .AppleWatch1,
            "Watch1,2" : .AppleWatch1,
            "Watch2,6" : .AppleWatchS1,
            "Watch2,7" : .AppleWatchS1,
            "Watch2,3" : .AppleWatchS2,
            "Watch2,4" : .AppleWatchS2,
            "Watch3,1" : .AppleWatchS3,
            "Watch3,2" : .AppleWatchS3,
            "Watch3,3" : .AppleWatchS3,
            "Watch3,4" : .AppleWatchS3,
            "Watch4,1" : .AppleWatchS4,
            "Watch4,2" : .AppleWatchS4,
            "Watch4,3" : .AppleWatchS4,
            "Watch4,4" : .AppleWatchS4,
            "Watch5,1" : .AppleWatchS5,
            "Watch5,2" : .AppleWatchS5,
            "Watch5,3" : .AppleWatchS5,
            "Watch5,4" : .AppleWatchS5,
            "Watch5,9" : .AppleWatchSE,
            "Watch5,10" : .AppleWatchSE,
            "Watch5,11" : .AppleWatchSE,
            "Watch5,12" : .AppleWatchSE,
            "Watch6,1" : .AppleWatchS6,
            "Watch6,2" : .AppleWatchS6,
            "Watch6,3" : .AppleWatchS6,
            "Watch6,4" : .AppleWatchS6,
            "Watch6,6" : .AppleWatchS7,
            "Watch6,7" : .AppleWatchS7,
            "Watch6,8" : .AppleWatchS7,
            "Watch6,9" : .AppleWatchS7,
    
            //Apple TV
            "AppleTV1,1" : .AppleTV1,
            "AppleTV2,1" : .AppleTV2,
            "AppleTV3,1" : .AppleTV3,
            "AppleTV3,2" : .AppleTV3,
            "AppleTV5,3" : .AppleTV4,
            "AppleTV6,2" : .AppleTV_4K,
            "AppleTV11,1" : .AppleTV2_4K,
            "AppleTV14,1" : .AppleTV3_4K
        ]
    
        guard let mcode = modelCode, let model = modelMap[mcode] else { return Model.unrecognized }
        if model == .simulator {
           if let simModelCode = ProcessInfo().environment["SIMULATOR_MODEL_IDENTIFIER"] {
              if let simModel = modelMap[simModelCode] {
                return simModel
              }
           }
        }
        return model
    }
}

Usage: You can simply get the device model with:

let deviceType = UIDevice().type

or print the exact string with:

print("Running on: \(UIDevice().type)")
Output -> "iPhone X"

Another example with cases:

var myDefaultHeight: CGFloat = 30.0
switch UIDevice().type {
    case .iPhoneSE, .iPhone5, .iPhone5S: print("default value")
    case .iPhone6, .iPhone7, .iPhone8, .iPhone6S, .iPhoneX: myDefaultHeight+= 5
    case .iPhone11, .iPhone12, .iPhone13: myDefaultHeight+= 10
    default: break
}

For Apple devices models visit:

NOT UPDATED ->h.t.t.p.s.://www.theiphonewiki.com/wiki/Models https://theapplewiki.com/wiki/List_of_iPhones

P.S.: I've made a little new asyncronous experiment here (direct connection with THEIPHONEWIKI site, without long static device list in source code.