The 77mm Swift Magnetic Lens Adapter Ring from H&Y Filters is a Swift System A Module adapter ring. It allows B Module and C Module accessories to be added to a lens with a 77mm filter thread, and is compatible with wide-angle lenses. This adapter is built with magnetic thread that can work with Magnetic Clip-on Filters, and then Swift Magnetic Bridge ring on top of it, Swift Magnetic Drop-in Filter Rack, and Swift Magnetic VND filters to be compatible with accessories like Magnetic Matte Box, Magnetic Square Filter Holder, and Magnetic Collapsible Lens Hood.