This is the cordless knee wrap that uses patented heating technology to improve circulation, relax tight muscles, and relieve joint pain. The wrap is made from flexible, mild-compression neoprene lined with fleece, and it comes with two adjustable hook-and-loop fasteners that keep it securely in place around the knee. Virtually undetectable stainless steel fibers that are woven onto an insulated fabric to generate deep-penetrating heat that adjusts to four different levels of warmth ranging from 91° F on low to 114° F on high. Its included slim lithium-ion battery secures inside an attached hook and loop fastener pouch and automatically shuts off after 30 minutes of use. A four-hour charge via its included AC adapter provides two and a half hours of power on the highest setting. One size fits most. 12" L x 8" W x 2" D. (2 lbs.)