This cooling vest adopts water evaporation physical cooling technology with built-in energy-absorbing polymer cooling filler. No power supply or pre-freezing required; cooling effect is activated by adding water. Crafted from moisture-permeable polyester fabric, it retains water to continuously absorb heat via evaporation, lowering perceived skin temperature to 20‑28°C and delivering 4–8 hours of lasting coolness, reusable for more than 100 cycles. It features pure physical cooling without any chemical additives, safe for repeated recycling.