1.[AIR OUTLET TEMPERATURE THERMOMETER]Only manual knob and adjust air outlet temperature thermometer. In normal circumstances, the outlet temperature of the vortex tube will be maintained at ±1℉ (±0.6 ℃) continuously. This welding air cooling vest is no electricity, freon or chemical refrigerant, only filtered compressed air for industrial use. 2.[EASY TO USE]This welding cooling vest is easy to use. Instant on / off, easy to control, cooling does not produce any waste.This is a personal cooling solution for those who want to prevent their body from overheating. Vortex tube air conditioning clothing is the most effective, quickest, most economical and easiest way to lower human body temperature known. 3.[NO NEED TO UP]This air conditioned vest is no need to components, no need to residue. The nylon and oxford fabric material and sleeveless design ideal for warm climates or summer adventures. It can be worn inside and outside, long term comfortable wear, temperature can be adjusted, and can meet the heat insulation and mixed combustibility test. 4.[WIDE GE]This air conditioner jacket fits most sizes with adjustable sides and shoulder straps. Easy pull, slide and zip to fit. Suitable for high temperature, high fever, high humidity, specially for cold labor environments. Such as metallurgy, forging, welding, glass, fire, power plant, boiler plant, sandblasting, paint baking, and so on.