Product Details:

Instructions 
1. Rinse the shower bag with one tablespoon of baking soda and warm water before initial use.
2. Fill the bag with water, then place it on a flat surface with black side up and directly expose to the sunlight.
3. Maximum temperature should be attained in approximately 3 hours; it can make the 15℃ water reach about 45℃.
4. Please test the water temperature before use since it maybe reach 50 Celsius degree in the strong sunshine.