Strong Solid Plastic PP3 9 Volt  Battery Snaps.

100mm long lead with molded centre-positive 2.1 x 5.5mm DC connector. Great for powering Arduino or other similar boards off a battery. 

Fits 6LF22, LS9V, GP1604G-C1, 6LR6, MN1604, 6LP3146, 1604AU, CRV9, KF00492, 6LR61 and many more  batteries