The very latest in lens cap technology, OP/TECH USA's CONVERTER CAP offers photographers a stay-on lens cap while still allowing filters to be quickly added and removed. The CONVERTER CAP lens cover is watertight and dust-proof thanks to the O -ring seal. Once the metal ring is attached to a lens or filterit becomes an integral part of the camera. The base of the cap stays in place when the hinged, spring-loaded lid is flipped open by a flick of the thumb. The custom metal ring offers additional threads that will receive another filter so shooting options remain flexible. In addition, the CONVERTER CAP functions as aprotective guard against impact for not only the lens but also the rim of the camera or filter. For protection and convenience in a lens cover, the CONVERTER CAP is the solution. Once photographers try the CONVERTER CAP they'll be convinced that it is the last lens cap they will ever need. CONVERTER CAP is proudly made in the U.S.A.