To choose the perfect muzzle for your dog you'll need the following parameters: circumference around snout, while the mouth of the dog is opened (see image), length of the nose and height of the nose at the nose tip. If you add one plus centimeter to all of these parameters, you'll get the correct muzzle size which will be comfortable for your dog even in hot summer.
10-20 KG Dogs - Circumference: 26cm - Length: 10cm - Height: 7cm
Medium(Usually Mali Female Size): Circumference: 32cm - Length: 13cm - Height: 9.5cm
Large(Usually Mali Male Size): Circumference: 36cm - Length: 13cm - Height: 11cm