PIP Boss Therm Heated Baselayer Vest - Black 300-HV100 Designed to warm and maintain core body temperature, the breathable soft-shell material is an ideal base layer providing lightweight warmth, comfort, and versatility. The active fit one size fits all vest includes two-way locking Velcro straps, easy to adjust for a secure, unrestricted fit for any body type. FEATURES: Designed to be worn as a baselayer over a shirt, or any thermal garment. Lightweight, active fit one size fits all includes durable two-way locking velcro straps. Heating elements located on the chest and back, warming a large surface area to promote blood circulation, relief from muscle pain, enhance metabolism and improve immunity. Low, Medium, High temperature ranges. Quick rechargeable 5V power bank provides 8+ hours of warmth on a single charge*. Machine washable; Heating elements are designed to endure 50+ washing cycles. Includes battery operated remote control and initial battery. Additional batteries available: 399-HVBAT. Replacement remote: 399-HVRE. SPECIFICATIONS: MaterialNylon SizeOne Size Fits Most ColorBlack Low Heat Setting90° F Medium Heat Setting115° F High Heat Setting135° F PIP Boss Therm Heated Baselayer Vest - Black 300-HV100