Designed for rehabilitation and physical therapy of chronic, acute and post operative pain, this TENS unit works by sending stimulating pulses across the surface of the skin and along the nerve strands. The stimulating pulses help prevent pain signals from reaching the brain. TENS units also help stimulate your bodies natural endorphins. Features dual isolated channels, adjustable intensity control and pulse frequency. Comes complete with carrying case, 2 lead wires, 9-volt battery, 1 package of 4 pre-gelled electrodes (replacement electrodes #A2099 sold separately) and operating manual. ABS, aluminum and electronics. 10 1.2"L x 8"W x 3"H. Wt. .99 lbs. This item ships from a separate warehouse and will arrive in a separate package.