It appears to be Grohe -- There's a good chance that stem/cartridge is discontinued, if not, it's going to be pricey. Whats you problem -- water temp not working proper , continous leak/dripping when valve is off , water pressure problem ?
its just like it except the end that goes in first mines plastic on the end and the new one has a o ring on that end also, I'll call to figure out the rest tyvm