Quantity   Component name
1 × 3D printed parts from PETG PETG or stronger is ideal due to flexability and strong inter-layer adhesion. PLA may work but not recommended.
1 × PCB protected (against under-voltage) 18650 cell These are easy to find over amazon, aliexpress, ebay, etc. as high power flashlight batteries. You can also salvage them from laptop battery packs, cheap powerbanks, discarded Teslas, Powerwalls, etc. but salvaged cells must have a under-voltage PCB added. These PCBs can be sourced from aliexpress.
2 × Wire Approx 100 mm total
2 × Flat copper strip, or metal strip Those plastic/metal anti-theft magnetic sticker markers contain 3 usable strips each!
2 × M2 Screw, 4mm Longer is not recommended as they will poke into the battery.
2 × Small spring For interfacing the wire to the battery. Can be replaced with wad of aluminum foil in a pinch.