Milwaukee® M12™ heated hand warmer - powered by M12™ REDLITHIUM™ Battery technology, Milwaukee® M12™ heated hand warmers integrate (2) carbon fiber heating elements between a durable wind and water resistant exterior and thermal fleece liner to heat your hands and help maintain dexterity. Insulated dual cuff construction combines with your outer layer to form a wind proof seal and keep the weather out, even on the coldest days. Featuring dual cuff construction that forms a wind proof seal in combination with your outer layer, the hand warmer reduces the need for bulky gloves on or off the jobsite.