When your dog wears a collar, be careful not to make it too tight, as a too tight collar can cause harm to your dog when it suddenly runs or rushes excitedly. A suitable collar should have room for the owner to put two fingers in after the dog wears it.
Neck circumference measurement
When buying a collar, you will usually see a mark on the neck that says neck circumference x cm~x cm. Usually, the first number represents the length from the dog's jaw parallel to the back of the neck, and the second number represents the length from the junction of the neck and the back parallel to the back.
1.5cm collar: Neck circumference 26-33cm, suitable for small dogs
2.0cm collar: neck circumference 30-39cm, suitable for medium-sized dogs
2.5cm collar: Neck circumference 37-46cm, suitable for large dogs