Plug your unit into the wall or use battery-your choice. How about that? Never run out of power, and never buy another battery again for your unit. This unit works off of A.C. and battery inputs...your choice! Dual Power-means A.C./D.C. Dual Power-Boasts 120 Volt and battery capabilities all in one super high quality unit. *About Photo The photo shown is NOT the actual unit, but a close representation. *Comes with the following: Instruction booklet 2 packs of 2 square type peel-n-stick electrodes 1-9volt battery 1-a.c. type adapter (for plug in) 2 wire leads for 4 electrode pad placement at the same time. 1-pack of Biofreeze sample (Biofreeze is a unique and useful tool. We'll let you decide how to use it. It contains ILEX, which is a an herbal extract from a South American holly shrub. It is a fast acting, deep penetrating, long lasting analgesic gel that is icy cold and has no lingering scent, it is nongreasy, and it won't stain clothes or skin.)