The thinnest FIR heated compression Vest Liner in the world. Designed to comfortably fit under any outer layer. Convert your favorite Leather jacket, Winter Parka, Down Jacket, Hoody, motorcycle jacket, ski/snowboard jacket into a heated jacket at a fraction of the cost without sacrificing your sense of style. Control Vest temperature with your smartphone with our new free app available for Android and Apple devices. Click here for Android or Apple. Both available on your app store. Search "firedup". Please ensure you location is set to on to connect via Bluetooth. Now compatible with 12 V Lighter Power Socket for all day unlimited power for Motorcycle, Snowmobile and Cars. FIRed Up heated vest liners use F.I.R (Far Infrared) heat to keep you warm in the harshest of conditions. FIR produces a soothing and therapeutic heat that is safe and reliable. There are no metal wires in the vest which means no chance of wires breaking or coiling and creating hot spots that may burn the user. Infrared heat is how the Sun heats up the Earth. Our own bodies emit Far Infrared heat to keep us warm. Features: Made from a thin Stretch Fabric for a comfortable fit under any outer layer Multiple temperature settings controlled manually or via Smartphone with Bluetooth connectivity and free application Heating Zones are located as follows: Chest Left and Right, Large Middle Back. Largest heating pads in the market Included are Two 12V Super slim Lithium Polymer Batteries. Battery duration will depend on how cold it is and what outer layer you have on top. Based on that each battery will last anywhere from 2 - 4 hours depending on the setting Universal Voltage Charger (adapter not included) Machine Washable Why Far Infrared Liners: Safety: Far Infrared heat is the safest heating technology available. There are no metal wires inside. Heat is produced by Carbon Fiber filaments which emit Far Infrared light. So they will never overheat and burn the user. Reliability: The F.I.R. heating pads have an average lifespan of 80,000 hours. So no wires breaking or kinking/coiling creating hot spots. Health Benefits: Far Infrared Heat is known to help with blood circulation, healing tissue, healing muscle, help with chronic back pain, relieve Raynaud symptoms plus many more benefits described in a section below. Style: We all have a favorite jacket, sweater or hoodie that we love. We even have favorite gloves or thermal socks we use to stay warm. Don't compromise your sense of style! By using our FIR heated liners underneath that favorite outer layer add the desired heat with our multiple temperature setting control button. They can be worn comfortably under a motorcycle jacket, ski/snowboard jacket, leather jacket, work jacket, hoodie, sweater, parka, wind breaker or any other outer layer. The glove liner is designed to be worn under any outer layer of gloves with minimal loss in dexterity. Sock liner can be worn under any outer layer of sock or by itself. Ease of Use: From the temperature control button, which is conveniently located on all the liners, you can turn the heat On/Off or adjust the temperature settings with a simple touch. Practicality: The heating pads in the Vest/Jacket Liner as well as in the Sock Liner are waterproof and removable, allowing for easy machine washing. The glove liner can also be machine washed without the battery. Therapeutic Benefits of Far Infrared: Helps with rheumatoid arthritis Infrared heat increases the extensibility of collagen tissues Infrared heat helps decreases joint stiffness Infrared heat helps relieve muscle spasms Infrared heat treatment leads to pain relief Infrared heat increases blood flow Infrared heat assists in resolution of inflammatory infiltrates, oedema, and exudates Infrared heat improves soft tissue injury Sizing Chart: Heated Vest Liner Size Chart. Extra Small (Womens XXS, XS, S, M) (Mens XS, S) Chest Circumference - 26" - 36" ( 66 cm - 91 cm) Shoulder to Shoulder - 12" - 16" ( 30 cm - 40 cm) Waist Circumference - 22" - 34" ( 55 cm - 86 cm) Medium (Womens L, XL) (Mens M, L) Chest Circumference - 36" - 42" ( 91 cm - 106 cm) Shoulder to Shoulder - 16" - 19" ( 40 cm - 48 cm) Waist Circumference - 34" - 38" ( 86 cm - 96 cm) Large (Womens XL, 2XL) (Mens L, XL) Chest Circumference - 42" - 50" (106 cm - 127 cm) Shoulder to Shoulder - 19" - 24" (48 cm - 60 cm) Waist Circumference - 38" 42" (96 cm - 106 cm) 2 XL (Womens 2XL, 3XL) (Mens XL, 2XL, 3XL) Chest Circumference - 45" - 60" (115 cm - 152 cm) Shoulder to Shoulder - 22" - 29" (55 cm - 73 cm) Waist Circumference - 42" - 50" (106 cm - 127 cm) Fired Up X Infrared Heated Vest Liners with Smartphone Temperature Control Application