Cover Ring Adaptors are special mounts that attach to the objective lens of a day optic. This allows for the installation of additional devices such as front mounted NV or thermal units, etc.
Insert Rings are moulded to fit specifically sized objective lenses. This ensures that the Cover Ring Adaptor Attaches to the objective lens housing safely.
Please Note that Cover Ring Adaptors and their inserts can remain on a day scope to act as a protective cover when not in use.