The Milwaukee L4HBLB-301 is an XL usb rechargeable work skin heated base layer. The base layer has 2 heat settings and has a max run time of 180 minutes on the low setting. The item is made of 100% polyester and is machine washable. L4HBLB-301 XL size 1 x L4 b3 battery pack 100% polyester 2.5 minutes to fully heat up chest and back heat 2 heat settings 180 minutes run time on low setting machine washable