RinbowImaging 43mm Metal Screw-in Lens Cap / 43MM Stack Cap Protect store Filter case This item can work as a 43mm Metal Screw-in Lens Cap, and it can also work as a 43mm Filter Stack Case. Filter case protect filters from dust and scratches while they are not being used Simply screw the filters together, then screw these stack caps on the top and bottom. Compatible to lens with 43mm thread size, and 43mm Filters