The Rock Exotica OMNI BLOCK® is a mix of the old and the new. Rotating swivel pulleys, called "blocks" in years past, have been around for centuries with drawing dating back to ancient Greek inventor, Archimedes (The first know recorded source of the common pulley system). Originally the first such pulleys were carved and fashioned from actual blocks of wood reinforced with metal banding to prevent the wood from splitting under load. Up to now, rescue pulleys have been the standard side swing plate models that involve rotating the side plate and the introduction of the rope into the sheave. Increased strength is cited as the main reason that life safety pulleys are designed this way. Incredibly quick to attach, the Rock Exotica Omni Block is a high strength (36 kN), swiveling rope block/pulley. Like RE’s popular swivel connector, these pulleys eliminate twisting from rope rigging systems with smooth, ball bearing action. Each precision fabricated alloy block has a unique button-activated release feature that allows instant access to the sheave for midline attachment. The milled alloy attachment eye is large enough to accept most carabiners and snaps. Pulley 1.5" and accepts up to ½" rope.