A steel bolt has weakening grooves at one end to which a head is swaged, the head having two frusto-conical portions at opposite ends. One end has a frusto-conical step for receiving a pair of jaws of a bolt breaking tool. A resilient spacer is attached to the bolt next to the head for limiting the depth of entry of the bolt head into a hasp hole, to provide access clearance for the tool and to permit the bolt to tilt to assist in breaking the bolt. The spacer is received in one hasp hole smaller in diameter than a second hasp hole to limit the depth of insertion of the spacer and the bolt head tapered end portion into the hasp. A seal with a conventional locking mechanism has a frusto-conical end region which partially engages the other hasp hole. The bolt and seal cooperate to lock the seal axially at different positions so the seal is engaged with one hasp hole and the bolt head engaged with the other hasp hole. A tool is disclosed which mates with the bolt head for breaking the bolt at the head when used with J-shaped hasps with limited tool receiving space.