The Pentax Rear Lens Cap is designed specifically for K-Mount lenses, including K, PK, KA, KAF, DA, and FA series. It is compatible with a wide range of Pentax lens models such as SMC Pentax-F, M Prime lenses, and K series lenses. The cap features a twist-on fastening mechanism for easy attachment and removal. Made by Sonia, this unit is a universal rear lens cap designed for Pentax K-mount teleconverters and adapters, as well as FA zoom lenses and FA J zoom lenses. Crafted in India, this rear lens cap ensures the safety of your valuable lenses when not in use.