I: Designed for internal wear. it's best to wear a suit or jacket outside.New Updated Heated Vestheated down vest works as a personal radiator to keep your body warm anytime. As one of heat therapy. the vest can promote healthy blood flow that increases the oxygen and nutrient flow to muscles. relieving pain. decreasing recovering time and improving overall performance. It is specially designed for most of the people like cold weather workers and others performing outdoor activities (like cycling. hiking and other winter sports).11 Updated Heating AreasThe professional heating vest Increases more heat areas. compared to other old heating clothes. they have only 5 heating areas. Our new vest covers 9 heating areas. built in with quality carbon nanofibers heat elements due to its quick heat-up technology. lightweight. flexible & safe to use. Generate consistent heat for many acupuncture points and meridians. including your back. abdomen. sholder and waist. helping to maintain body warmth.3 Power Switches & 3 Heating LevelTriple-switch design Should. Waist & Abdomen switch can be operated separately. 3 heating level from 40/ 104 to 65/ 149. Customers can choose how to heat the heating pads according to your own demands. Your body will be comfortable and does not sweat because of overheating. and comfort as spring. And the individually controlled design makes your device more power-efficient and more durable.Safety AssuranceBuilt-in thermal protection module. Once it is overheat. it would stop until the heat return to the standard temperature. so it is 100% safe to use. Work with common power bank with common USB port. you can choose High-storage power bank or prepare multiple batteries in advance. (Power bank is not included)Quality Guarantee & Best Customer Service Please choose the right size according to the size chart. Best of all. by buying with us. SIZE:CM M: LENGTH:65 CHEST:106 SHOULDER: 40.3 L: LENGTH:67 CHEST:110 SHOULDER: 41.5 XL: LENGTH:69CHEST:114 SHOULDER: 42.7 2XL: LENGTH:71 CHEST:118 SHOULDER: 43.9 3XL: LENGTH:73 CHEST:122 SHOULDER: 45.1 4XL: LENGTH:75 CHEST:126 SHOULDER: 46.3