The next generation ISC Rigging Pulleys are up to 150% stronger than the equivalent ISC standard Rigging Pulley models. The new low-profile Spring-lock mechanism features a new Safelock locking button to offer further security and ease of use. Simply push the Safe-lock button and turn the axle head 180� to the release position. The Safelock button can be depressed and the pinhead rotated in a continuous one-handed action. When the device is in the open position, the locking pin on the axle is retained in the correct alignment. This means that the user does not need to rotate the axle in order to correctly align the axle pin with the groove in the pulley plate, in order to close the device. Once the axle is fully depressed and the axle spring is fully compressed, the axle head must then be rotated 180� (in either direction), at which point the Safelock button engages to lock the axle head in place.