Now that we have it narrowed down to only a flat collar with either a quick release or breakaway clasp, you'll want to choose one that correctly fits your Pug in regard to both weight and diameter.
The material that the collar is made of along with its thickness will determine how heavy it is and therefore how much weight will be placed on a Pug's neck. Flat collars (the type recommended for this breed) can be found in an array of materials that include leather, polyester or nylon webbing. Let's look at the choices:
This is a cheap material that is made from synthetic polymers. This low quality fabric wears out extremely quickly, absorb and hold body oils that can lead to terrible smells and are not a good choice.
These collars can look very stylish though the downsides are that these are not waterproof and some cheaper leathers can stretch out over time.
Webbed nylon, flat collars with a quick release or breakaway clasp are the best choice for most Pugs. A quality collar made of nylon webbing will be weather resistant, washable, resistant to odors and sturdy.
The general rule of safety and comfort is that once the collar is on, you can easily slip two fingers between it and your dog's neck. This allows it to be loose enough to avoid any type of constriction but be tight enough that it cannot slip off or be easily snagged onto something. While the collar for your Pug will be adjustable, you'll want to make sure that as your puppy grows, it can be sized to still fit those two fingers underneath.
Pug puppies often wear collars sized for toy breeds, though this will change after the first year. Since the Pug is the largest of all toy breeds with an adult weight
of 13 to 18 pounds (5.89 to 8.16 kg), though many adults are 20+ pounds (9.07+ kg) and a relatively thick neck, the adult Pug often needs a collar sized for small and medium breeds as opposed to toy breeds.