As Carcigenicate pointed out, you can use array.array directly as a type annotation. However, you can't use array.array[int] or array.array[float] to specify the type of the elements.

If you need to do this, my suggestion is to use MutableSequence from collections.abc, since arrays implement all of the necessary operations: __len__, __getitem__, __setitem__, __contains__, __iter__, etc.

from collections.abc import MutableSequence

arr: MutableSequence[float] = array.array('f')

You've already accepted an answer, but since you tagged ctypes you might want to know how to create arrays of ctypes types:

>>> import ctypes
>>> ctypes.c_void_p * 1024                # NOTE: this is a TYPE
<class '__main__.c_void_p_Array_1024'>
>>> (ctypes.c_void_p * 1024)()            # This is an INSTANCE 
<__main__.c_void_p_Array_1024 object at 0x009BB5D0>