① 睡袋盖 There is sleeping bag cover with waterproof. You can use with vinyl for emergency situation and I recommend some ventilation in foot position. Emergency vinyle is cheap and more light than sleeping bag cover. ② 水袋硅袋 Use silicone water bag in sleeping bag. Boiled water in silicone water bag last more than 6 hours. It is more efficient and safe and money saving! Buy some pieces in mall.