Turn any battery pack into a power supply with this incredibly useful adapter. A high quality molded 2.1mm DC barrel plug is brought out to red (center positive) & black (ring negative) alligator clips. 2.1mm is a near-standard for electronics, so with this adapter you can easy clip and connect packs and wires to a power jack. Good for about 2 or 3 Amps of current and up to 24VDC.