Spring Loaded 510 Connector 22mm with Floating Pin 2 PCS

E-Projects 25EP51415K0 15K Ohm Resistors, 1/4 W, 5% (Pack of 25)

Battery Holder, 18650 x 2, Through Hole

Hammond 1590G Diecast Aluminum Enclosure -- Inches (3.9" x 2.0" x 0.9") mm (100mm x 50mm x 24mm)

yueton DC 36V 2A 16mm High Round Cap Waterproof Metal Momentary Push Button Switch High Flush Reactable Screw Terminals

MakerFocus 5pcs Mini Digital DC Voltmeter 0.28 Inch Two-Wire 2.5V-30V Mini Digital DC Voltmeter Voltage Tester Meter 5 Colours

BestTong 18650 Battery Case Holder, 2 Slots 3.7V DIY Battery Storage Box in Parallel or Series Plastic Batteries Case with Clips Pins Contacts for Soldering 2 x 18650 Pack of 2

Keystone 209. 1 Cell Leaf Spring Battery Contact, Spring Steel, Nickel Plating (Pack of 20)

Battery Holders, Clips & Contacts PCB PLSTIC BATT HLDR SMT 2 CELLS