This is the Oceanic Aeris F.11 Battery Kit with O-ring Features: The Oceanic Battery Kit for OCS, OCi, F11 includes: CR2450 Battery Battery Hatch O-Ring 4 Battery Hatch Screws Silicone Grease The Oceanic Battery Kit for OCS, OCi, F11 ensures trouble free operation and long life. The Oceanic Battery Kit for OCS, OCi, F11 includes CR2450 Battery, Battery Hatch O-Ring, 4 Battery Hatch Screws and Silicone Grease.