Router table ring inserts for Universal Drop In Plate (sears Item # 00937972000P Model # 37972) for quicker bit attaching and leveling for use with Craftsman Premium Die cast Aluminum Table - 37610. I'm in the process of making my own router table, Insert rings have 3/4 in., 1-3/8 in., 1-5/8 in., and 2-1/8 in. openings and a blank. I bought the sears universal drop in plate which did not come with the insert rings, so I made my own.

Keep your inserts organized. https://www.thingiverse.com/thing:2707465