The CORDURA ICE WATER COOLING VEST PRO has a 650ml water tank and can be used for approximately 2.5 hours. - Model Name: ICE WATER COOLING VEST PRO - Material: CORDURA - Battery Capacity: 3350mAh - Water Tank Capacity: Approximately 650ml - Usage Time: Approximately 2.5 hours (when battery is ON) - Size: Fits M to XL - Type: Side-attached type - Hand washable - Cools with frozen plastic bottles Thank you for viewing. This is a new item, but I did not purchase it here, so I cannot answer questions about its performance. It seems that the same product is also available on Amazon, etc., so please check there. I am not currently considering a discount. Please understand. If it doesn't sell at this price, I may run a campaign. If you are considering purchasing, please "like" the item.