Power Tool battery adaptor

I love working on cars and watch a lot of car shows on the various documentary channels. One thing I noticed was some of them would use a battery-drill 12v battery for bench and in-car testing of motors, locking mechanisms and such and thought it a great and fast handy idea. But they were using it clumsily with jamming wires under the battery connections or trying to clip or tape to them somehow.

I use a few tools from a reputable power tool manufacturer and have three of these batteries to rotate between tool, charger and standby and so decided to design and make an adapter for these batteries to use when testing a 12volt 'something' was required.