This is a bolt that has to have a combination to retract. You can set your own combination.
To Assemble:
Print the code wheels found in the raw files. RH means the bolt will extend out the right side, and LH out the left. The number afterward is the correct digit. Mount the body, then put the bolt into the body. Insert your code wheels with the correct digit facing the back, and then press the bolt all the way through. Turn the bolt so it is facing the front, and then mount the Catch.