The Union 1439 Left Hand Cast Rim Lock Black Enamel is a large case heavy duty lock intended for external doors and heavier internal doors. On external doors it should be combined with a BS rated deadlock to meet minimum insurance company requirements.  The deadbolt is locked or unlocked by key from either side, whilst the latchbolt is withdrawn by the turn of a knob from either side. Other Variations The lock is also available in a right hand version - this can be found in the related products. Please take care to select the correct hand of lock for your door.  The...