Automatic release - The automatic release for open face corner block PCA-1270 fits ropes up to 1/2'' diameter. This is the perfect device for people pulling logs with a QUAD (ATV). An ingenious device for releasing the rope from the pulley to allow a log to ‘turn’ into the trail. Depending on the distance the anchor tree is from the trail, you may adjust the automatic release to make the rope slip out of the pulley at the appropriate moment. Simply turn the chain link one-half turn around the rope and insert it into the metal cartridge. Ideal to use with a QUAD (ATV) when you don’t want to stop in the middle of the operation.