Yes , thermostatic valves are for 2 or more outlets. It's not worth the added cost to have one for 2 outlets maybe 3+ but not 2. Thermocartridges run about $150-500 As a plumber myself I would just get two normal shower valves. The total handles are the same lol. Thermostatic valves have hot and cold flowing past the thermovalve with out a shutoff. If the valve isn't working correctly and the internal stops you can have a cross connection hot and cold because again the volume control shut off is after the thermo valve it's live always! If you went to a show room they get commission on fixtures. If someone can't give a equel pros and cons to a suggestion.it's that good or bad. Or, they are pushing it on you. Have a extra $250 cartridge on hand for once the valve is flushed and checks cleaned then replace cartridge. Answer from CapPretend6677 on reddit.com