Surface mount to the door frame for easy installation. Recommended door thickness is 1-1/2 (38 mm) or more. Opens to 125. Door stopper is required to prevent breakage of the hinges and failure of the door. Durability: successfully passed 300,000 open/close private cycles. Compact and sturdy design combined with an exceptionally simple install. Adjustable depth 1/8" (3 mm), vertical 1/8" (3 mm), horizontal with spacer 1/16" (1 mm)