【Size】Fits perfectly on mattresses from 140cm x 200cm with a thickness of 5-30cm! Box type with anti-slip rubber all around. 【Material】Flannel (100% polyester) 【Smooth, skin-friendly feel】The box sheet is densely packed with microfiber, so it doesn't let warmth escape. 【Fluffy and warm】Soft and fluffy, the moist touch soothes and warms both body and mind. The natural feel is stress-free and comfortable to use. 【Moisture-absorbing and heat-generating】The box sheet generates heat through the adsorption heat generated when the moisture-absorbing and heat-generating microfiber absorbs moisture. It is an essential duvet cover for people who feel cold easily to spend the winter comfortably. 【High insulation・Doesn't let warmth escape】The moisture-absorbing and heat-generating microfiber layer of the bed sheet traps heat and moisture between the fibers, creating an air layer that maintains the humidity on the sheet surface in an appropriate state, and the heat retention effect lasts for a long time. 【Static electricity suppression】The bed cover has been treated with [anti-static] processing to reduce the generation of crackling static electricity indoors in winter. The moisture absorption of flannel also helps to reduce static electricity by trapping moisture between the fibers. 【Washable】The box sheet can be washed in your home washing machine, so you can always use it cleanly. It also dries quickly, which is convenient for washing in the cold season.