Auvon via Amazon offers its Auvon Rechargeable TENS Unit Muscle Stimulator for $39.99. Coupon code "HASR4PCV" cuts that to $21.99. Plus, free shipping applies. Deal ends September 24. Features include: backlit LCD screen 16 pre-programmed massage modes with adjustable intensity adjustable timer 8 reusable electrode pads up to 10 hours of run-time per charge