"Simply screw in the C.E. Smith Rod Safety Ring for Cast Bottom Rod Holders and stop worrying about dropping your rig. It's conveniently made to secure into the .5"" drain hole found at the bottom of the flush-mount cast-bottom rod holder from C.E. Smith (not included), the Rod Safety Ring gives you a convenient place you can tether your rod and reed, boat fender, or any other valuable you don't want to fall overboard. This part of your rod tether system is made of 316L marine-grade stainless steel. Quick and easy installation. Creates a connection point for your rod and reel tether system 316L marine-grade stainless steel Quick and easy installation"