The sheave with sealed ball bearings provides excellent efficiency. 

The swivel facilitates operations, allowing the pulley to be oriented under load. The opening gate on the swivel makes the pulley compatible with a wide variety of products (tripod, REEVE pulley, PAW rigging plates, and more) reducing bulk during set up.Possible to open, even when attached to the anchor, the SPIN S1 OPEN pulley is designed for maximum simplicity in setting up haul or load deviation systems and tensioned highlines. Compact, reducing weight and bulk, which is especially useful during technical rescue. The sheave with sealed ball bearings provides excellent efficiency. The swivel facilitates operations, allowing the pulley to be oriented under load. The opening gate on the swivel makes the pulley compatible with a wide variety of products (tripod, REEVE pulley, PAW rigging plates, and more) reducing bulk during set up