When purchasing a dog collar, the selection of material should be based on the following considerations:

1. Size and Breed of pet: Small dogs usually have the option of a lightweight collar, while larger dogs need stronger material. Different breeds also have different needs, such as dogs that need wider collars to support the dog's mouth.

2. Pet skin sensitivity: Pet skin can be allergic to certain materials, so choose a mild material. Cotton or leather collars are recommended.

3. Wear time and intensity of activity: If your pet regularly wears the collar and engages in high intensity activities, choose a more durable and strong material, such as nylon, to ensure the collar's stability and safety.

4. Preferences and style: In addition to the above considerations, consider the pet owner's preferences and style. For example, some owners prefer cute cartoon collars, while others prefer simple monochrome designs.

In general, buy a dog collar with materials that are strong, soft and breathable, and choose the right material based on your pet's size, skin sensitivity, length of wear and intensity of activity. In addition, you need to pay attention to factors such as the size, weight and ease of adjustment of the collar. Choosing the right materials will keep your pet comfortable and safe while also increasing the life of the collar.