The 49mm Magnetic HD Short Cross 4 Filter Kit from H&Y features a circular filter and two ND filters, all magnetic. A magnetic adapter ring is included that screws onto the 49mm front filter thread of compatible lenses. With this adapter ring attached, you can then magnetically mount and swap filters.
67mm magnetic step-up ring is included that can be screwed onto lens filter threads to magnetically support all the 67mm magnetic filters. With the magnetic adapter ring and this step-up ring in your toolkit, you'll be able to work with both 67mm threaded lenses. The kit is complete with a magnetic lens cap.