The GU 2 rollers & 2 mushrooms lift lever features 2 rollers for compression and 2 mushrooms for extra security. The 28mm backset version features a black plastic gearbox. Locking points are engaged by lifting the lever and locked by turning the key. To reverse handing, Push a flat bladed screwdriver into the small rectangular slot above spindle and pull out latch at same time. Reverse and reinsert.