Features Our heated insoles equipped with 3.7v 3000mAh upgraded battery & 5v 2A USB charger, provide fast charging (3 hours) and long time heating (10 hours): High Temp Mode - Red Light: 131-149℉ for 4 hours, Medium Temp Mode - Yellow Light: 122-131℉ for 6 hours, Low Temp Mode - Green Light: 104-114℉ for 10 hours. Our ski boot warmer are designed with smart chips, provide you with basic 3 kind of protection and pre-heating function, pre-heating: warm your feet within 30 second after start, automatically enter the high temp mode after reaching the predetermined temperature. Our heated shoe insoles design with built-in battery, made of very eva, excellent in absorb sweat, seismic and compressive, 0.6 cm thick shoe toe & 1.7cm thick heel, light and soft, both of them provide you comfort wearing. Our rechargeable heated insoles adopt premium heating element, heat gently and evenly, come with remote control, convenient to use, easy switch the heating mode, perfect to be a gift for the one who has cold feet, Achilles heel, inflammation, sore feet, arthritic feet, Raynaud’s etc. AZ2.70