Olympus PSUR-03 Underwater Step Up Ring Compatibility: Olympus PT-055 underwater housing for TG-830 Olympus PT-053 underwater housing for TG-1 and TG-2 Olympus PT-052 underwater housing for TG-820 Olympus PT-056 underwater housing for TG-3 and TG-4 Olympus PT-058 underwater housing for TG-5 Filter Diameter: 52-67mm