12oz Proper retraction force is essential for flashlight applications a | Too much force for heavy lights and Cameras will fatigue the user. Locking Mechanism is designed for securing light on land a | when diving, unlock unit and the moderate 12 oz retraction force will easily secure a flashlight or camera. Plastic Snap clip is durable and easily attaches to BCD D-rings. 18oz The Hanging Instrument Tether is recommended for hanging a bar code scanner on a forklift, assembly line or a retail environment. The snap clip allows the retractor to be attached to the cage on the forklift. The 18 ounce version is used on scanners that weigh more then 10 ounces and less then 18 ounces. 240z The Hanging Instrument Tether is recommended for hanging a bar code scanner on a forklift, assembly line or a retail environment. The snap clip allows the retractor to be attached to the cage on the forklift. The 24 ounce version is used on scanners that weigh more then 16 ounces and less then 24 ounces.