Note on the O-ring
What Is an O-ring?
•An O-ring is part of the water-proof packing that is used on underwater cameras, watches, and other diving equipments.
•The O-ring acts to preserve the waterproof qualities of the marine pack and other equipments.
O-ring 
How the O-ring waterproofs
O-ring
The surface of the O-ring contacts the rubber to prevent water from entering the gap.
When water pressure acts on the O-ring, the contact surface area of the O-ring expands to increase the force acting on the groove on the marine pack.
O-ring maintenance is very important. If O-ring maintenance is not followed according to instructions, this might cause a water leak, and cause the marine pack to sink. The surface of the O-ring contacts the entire rubber evenly to prevent water from entering the gap.
