Adafruit Industries Adafruit Industries 20mm CR2032 Coin Cell Breakout w/On-Off Switch
Simple but effective - this sewable breakout board has a CR2032 coin cell battery holder soldered on, an on/off switch and 0.1" pitch breakout pins for easy connecting. Great for powering very low-current projects, or adding a battery backup circuit to a real-time-clock or similar. There's two ground pins, one 'switched' power pin, and one pin that is always on.
Adafruit Industries 20mm CR2032 Coin Cell Breakout w/On-Off Switch
Usually ships in 1-3 business days.