MilWalt Battery Adapter 

 3 amp maximum  (if you need to power something more than 3 amps, use a relay)

This adapter fits both Milwaukee and DeWalt style batteries 

On the underside of the adapter is a small "blinker board" (low voltage cutoff) to protect the battery from over discharge. More information on the Blinker Board here.

Includes: 1 adapter with BB board

Fits:
Milwaukee M18 style tool battery
DeWalt style 20v tool battery

Battery not included