These two parts are custom made for the OE Lido Series Grinders. The thin, white nylon cushioning ring acts as a break between the locking ring, and the adjustment ring. The square profile rubber ring fits inside the adjustment ring to cushion and seal the grinds jar lip. These two parts, used in unison, help to reduce the chance of the locking rings sticking. This set is included with all LIDO 2 grinders as of 2/11/2015.