there is a flange that is 3 inches in diameter

Bradley S45-844 "Hfso" Hand&Foot Stay Replacement Part

Escutcheon — Chrome-plated

This unit replaces the Bradley Classic Model # S19-210YF and is also referred to as Model # S192140A1BDC00

The walls with which the fastener is used must also be 2-1/2 inches to 3-1/2 inches thick

Haws 8111FP Freeze Resistant AXION MSR Drench Shower w/ Plastic Shower Head Capacity-44 oz there is a flange thatHand Activation Wall Mount Full Body Coverage Area 1" IPS Supply Inlet Meets ANSI Standard Z358. 1 The HAWS model 8111FP is a freeze protected, wall mounted drench shower with AXION MSR ABS plastic showerhead. The unit also includes flow control for the showerhead, a brass stay open ball valve with stem and stem extension for maximum wall thickness, a stainless steel push flag, and a universal sign. From the Manufacturer: Model 8111FP AXION MSR freeze