Size: S size mouth length 8cm head circumference 24cm, M size mouth length 9cm head circumference 26cm, L size mouth length 11cm head circumference 30cm, with adjustment rope buckle FunctionThe anti-haze pet mouth can effectively prevent dogs from breathing allergies when they walk outdoors. MaterialThe cotton cloth it uses is breathable and safe, gentle on the dog's skin, and the elastic edge can fit snugly on the face. Adjustable StrapsYou can adjust the straps according to the actual size of the dog to ensure a firm fixation. There are buckles on the straps to prevent rebound, so there is no need to worry about the rebound of the straps and hurt the dog. Adjustable Steel RingYou can adjust the shape of the steel ring according to the dog's mouth shape to maintain the internal space.UsageIt is suitable for preventing industrial exhaust gas, automobile exhaust, pollen, second-hand smoke, smog, etc. from harming the dog's health. UsageIt is suitable for preventing industrial exhaust gas, automobile exhaust, pollen, second-hand smoke, smog, etc. from harming the dog's health.