The 30603 56mm Port Extension Ring for Select Olympus Micro Four Thirds Lenses from Aquatica extends the length of the lens port, providing the extra space needed to accommodate the lens. The port extension ring is installed between the underwater camera housing and the dome port and specifically fits Olympus M.Zuiko 12-40mm Digital ED f/2.8 PRO lens with the SW8 Dome Port. It is compatible with AE-M1, Amphibico Blackmagic Pocket Buddy and other Micro Four Thirds housings.