The 37mm-52mm Step-Up/Extension Ring enables mounting 52mm filters to a 37mm thread, and allows 6 mm of extra clearance for your rig. As an example, use the Step-Up/Extension ring to add any 52 mm filter to your iOgrapher case for iPad. The Ring also has a 37mm filter thread for extra flexibility to mount 37mm filters as well.
"I don't dream at night, I dream all day; I'm dreaming for a living." - Steven Spielberg