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 low voltage cutoff board ("blinker board") to protect the battery from over discharge. More information on the Blinker Board here.

Do not leave your battery attached when not in use, this may slowly drain the battery over time due to a small parasitic draw. However, the battery will still be protected from over discharge. 

Includes:
Battery adapter (1 pcs)
Blinker board - installed (1 pcs)

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

Bottom cover available here.

Battery not included