The REVORING 52-72mm Variable Adapter for 77mm Filters from H&Y Filters is a unique adapter ring to attach a 77mm filter on to a variety of lenses quickly. It features unique self-retracting blade technology with threaded ends to secure on the front of any lens with a filter thread size of 52-72mm. The overlapping blade design prevents unwanted light leaks. The retractable blades mount solidly on the lens. No more adapter rings will be needed to mount a large circular filter on different lenses. Note: Not compatible with any REVORING Magnetic Caps or any magnetic clip-on filter.