This a means for locking an automobile battery to its mounting plate so that it can't easily be stolen. It includes a special block and hardened material which serves to lodge a mounted battery in place against its mounting plate. A bolt is secured through this block to the mounting plate. The bolt has a head formed with a variably configured female locking receptacles which fits down in a recessed opening in the top of the block. A key male piece can be matingly received in this female head so that the attached bolt can be turned to lock or release the battery. The key can be removed and the recessed head becomes inaccessible for security of the battery.
