The inventive technology disclosed herein, in embodiments, relates to a shower stall system that may include an inventive shower drain adaptor ring 11; an inventive anti-ligature grab rail system 30; and inventive, drop-in shower installation related apparatus and methods. Note that all of these may find application in a prison environment, but may find application in other environments as well (e.g., grab rail in kitchen, shower drain adaptor ring in residential shower, etc.).