Abstract: A lock for use with a door having a latch which is adapted to be received in a notch located in the door frame can be utilized either as a permanently-installed lock or as a portable lock that can easily be moved to various locations. A planar member is adapted to be disposed between the door frame and the door when the latter is in closed position. A laterally extending tab is disposed at a right angle to the planar member and is adapted to be received in the notch. A pair of slots in the member are mirror images of each other and diverge away from a divider element that lies in a horizontal plane passing through the tab. Each slot is configured to present a plurality of seats for receiving a keeper pin adjacent the door, when the latter is closed, to present a dead bolt lock. By simply turning the member 180.degree. the lock can accommodate either a left or right-hand opening door with the opposite slot being utilized for each position of the member.