Due to State and Federal Law, we sell Syringes and Needles only to the Medical Facilities. Tens Kits includes: Tens Unit, reusable electrodes (PK/4), lead wires, instruction booklet and hard carry case with handle * Timer has 3 settings: 30 minutes, 60 minutes or constant * TENS 200 features: Mode selector: B (Burst), N (Normal), and M (Modulation) * PRO-TENS features: Mode selectro: B (Burst), N (Normal) and M (Modulation) with a Timer * Dual isolated channels, two leads per channel * Pulse amplitude (constant current) * Adjustable 0 - 80 mA, 500 Ohm load * Pulse frequency: Adjustable 2 - 150 Hz * Pulse width (micro seconds): Adjustable 60 - 250 * Wave form: A symmetrical, Bi-Phase, square pulse * Uses 1ea - 9 Volt battery included Shipping Carton Size: 12"L x 10"W x 6"H