Help identifying shower valve and cartridge
Looks like an American Standard, hard to tell as your bottom photo is not that great. 

https://www.supply.com/shop?nid=567051&amp;d=1124-16385&amp;wmh_cid=236648182&amp;wmh_aid=14658639502&amp;wmh_kid=69378820539&amp;gclid=Cj0KCQjw_o7NBRDgARIsAKvAgt3kDpHmf2lHcIlhVOvT-_RT2EC3H95CkP3ieOXSRCL3rAhEJijbyEQaAhZmEALw_wcB