The threads for the battery compartment on a det210 from thorlabs must have galled. I forced it apart since the device could no longer be biased with a dead battery. Realized a 9V battery would be easier to replace than the original battery was, so came up with this. 3d printed piece acts as an insulator/anti-rotation device to keep the 9V battery from flopping around and shorting out. Requires disassembling the det210 and drilling/tapping/soldering a bit. Battery connector is a keystone 968 https://www.keyelco.com/product.cfm/product_id/1072