Dummy AA battery enables you to use a wired power supply or different size batteries when necessary. I used it to adapt a AA charger to charge D batteries in a separate holder.

Printed in PLA, insert wire with crimp ring in slots on either end, screw in a pan head #8 screw at each end to hold in place and provide contact surface. Negative end will be recessed/flush with battery end. Positive screw will protrude.