Specifications: Lightweight insulation allows you to wear in a variety of ways in unrestricted motion; waterproof and windproof. Vest has function of 3 seconds fast heat 0 radiation safe fast and smooth heating without radiation. It is suitable for outdoor activities such as snowmobiling motorbikes hiking camping hiking skiing fishing hunting ect. The vest is heated by USB and needs a 2A power bank (Not Included). Item Name: Vest Material: Self-heating Cotton Fabric Elastic Cloth Crystal Super Soft Fabric Size Type: Regular Gender: Men Women Style: Stylish Features: Warm Keeping Zip Closure with Pockets Size Details [Our Size M] Shoulder: 38cm/14.96 Sleeve: 10cm/3.94 Length: 60cm/23.62 (Approx.) [Our Size L] Shoulder: 40cm/15.75 Sleeve: 10cm/3.94 Length: 61cm/24.02 (Approx.) [Our Size XL] Shoulder: 42cm/16.54 Sleeve: 10cm/3.94 Length: 63cm/24.8 (Approx.) [Our Size XXL] Shoulder: 44cm/17.32 Sleeve: 10cm/3.94 Length: 65cm/25.59 (Approx.) [Our Size XXXL] Shoulder: 46cm/18.11 Sleeve: 10cm/3.94 Length: 68cm/26.77 (Approx.) Notes: Please refer to our size chart and choose the right size. Due to the light and screen setting difference the items color may be slightly different from the pictures. Package Includes: 1 x Vest