【Premium Material】The hot water bottle covers use double-layer velvet fabrics (95%polyester+5%spandex), which helps to isolate the hot water, prevent the skin from being burned, and keep you warm for about 6 hours. 【Excellent Leakproof】The hot water bottle is made of PVC, and the lid is made of PP. The wide mouth design is easy to fill water. The sealed bottle cap helps prevent water leakage. 【Size & Note】Two sizes are available of the hot water bottle. S: 15.5*25cm / 6*10in (1L); M: 20*30cm / 10*12in (2L). Note that filling water can only be filled with 2/3, and the hot water bag is machine washable.