Adafruit-1871-Adafruit-20mm-Coin-Cell-Breakout-with-On-Off-Switch-CR2032-Adafruit-1871-P-The-Adafruit-CR2032-Coin-Cell-breakout-board-is-a-quick-&-simple-way-of-adding-primary-or-backup-power-to-your-projects-it-s-even-sewable-for-your-next-wearable-project-The-four-output-pins-are-on-a-0-1in-pitch-for-breadboarding-&-provide-2-x-GND-1-x-3V-&-1-x-switched-3V-P-P-Supplied-fully-assembled-&-tested-but-without-a-battery-We-stock-plenty-of-suitable-A-href-lithium-batteries