The battery protection cover is made of neoprene, with a double-sided fleece design, and the thickness is 4.5 mm. it has strong waterproof, anti-freezing, sun-proof, cold-proof functions, effectively protect your battery from low temperature, keep efficient battery performance. This bicycle battery protector can provide all-around protection for the battery in harsh environments (blizzard, rain, severe cold), avoid excessive consumption of power, thereby extending battery life.