Eyepiece locking ring presses over mounted eyepiece locking the rubber in place so eyepiece wont come off accidentally.

Push eyepiece thru ring make sure thick side of locking ring is away from the device. When you mount the eyepiece push the locking ring flush with the end of the eyepiece. This will lock the rubber in place and it wont come off accidentally. Fits pvs14 style eyepieces. Holds on very tight, I have this on my MKIII 60mm and you can hold it from the eyepiece without it detaching.

Printed with PETG