I wore this once for work, but it didn't suit my workplace environment, so I'm selling it as I haven't used it in a while. The box is torn, and I will use tape etc. for packing when I mail it, so please understand. Cool vest with water cooling, capable of cooling for up to 4 hours. Equipped with a 5200mAh battery. - Model Name: DC-B02S(B) - Battery Capacity: 5200mAh - Cooling Method: Water Cooling - Cooling Duration: Approximately 2 hours - Maximum Cooling Time: Approximately 4 hours - Water Tank Capacity: 650ml Thank you for looking.