Infrared, flush mount, shower control.  Design features include a 16 gauge stainless steel wall plate, slow closing solenoid valve with strainer inlet, and an auto shut off feature after 8 minutes.  All components enclosed in a metal 5-1/4 x 6-1/2 recessed cabinet. Hardwired transformer supplied separately, part number 04-021.  Each transformer can power up to four units.