Review on 2-Pack Heated Knee Massager with 7.4V 6000mAh Rechargeable Battery - Electric Knee Wraps for Pain Relief, Arthritis - Adjustable Temperature & Vibrating Massage - Knee Warps for Better Recovery by Bishop Richter

That's a great idea. Easy to charge, easy to use. The knee pads are wearable so you can walk. The pain relief is amazing. My only problem was that I wanted to add a 3 year warranty within 4 hours of delivery. I thought it would be easy. To my surprise, Revane wanted me to return the original item and reorder. What a waste of money and time for shipping. There has to be a better way to do this. So if you want a 3-year guarantee, order this at the time of purchase. They are covered by a 1-year manufacturer's warranty.