This 40.5-58mm MCS Step-Up Adapter Ring from Tiffen allows Magnetic Control System filters to be quickly and securely attached to the front filter threads of a lens, eliminating the time and effort of threading filters on and off your optic. Step up from a lens's filter thread size to an MCS 58mm, 77mm, or 82mm filter. Installation is fast and easy and tools are not required. Versatile and easy to use, the adapter ring is also compatible with the 58 MCS protective lens cap, so the lens and filter will be protected when not in use.