Roller operates on push / pull action Bolt extends from 9mm to 20mm when thrown Ideal for flat and communal entrance doors Prevents accidental lock out Case Only - Order Rim cylinder separately The Asec Rollerbolt Nightlatch is ideal for flat and communal entrance doors. It does not lock automatically in the way a standard nightlatch would. Instead the roller operates on a push / pull action which helps prevent accidental lockouts. The bolt can be deadlocked or withdrawn by the key from the outside or by the lever handle from the inside.