Rainbow Filter Lid Lockring 172214 - Suits RTL, RCF & RDC style Rainbow filters - New version

Rainbow filter lockring

24 ribs on outside, marked - '172214', 'LOCK RING'. 'ON', 'OFF'
Buttress thread 

New version:
188mm OD, 170mm thread ID 
not notches.

This decrease in thread diameter 'may' make this lock ring too tight to fit. In this event, either the thread on the lockring and/or filter canister needs to be filed down, or complete filter replacement is required.

Original version:
188mm OD, 171mm thread ID
Had 4 square notches in the top inner flange.