There is a variety of equipment available to use during your Pug's training.
Start with the basics, pay attention to how your dog responds to them, and try to make decisions based your dog's successes rather than failures.
For basic obedience training, a simple flat buckling collar and a 4 to 6 foot leash is ideal. Double-stitched nylon is sturdy and long-lasting, and high quality nylon is even machine-washable. Avoid leather, as it shrinks and is easily chewed. Harnesses may be used on very young puppies, but avoid them for long term use, as they may promote pulling. Retractable leashes will encourage your dog to walk ahead of and lead you, and should also be avoided.
Choke chains and prong collars commonly used in training classes are designed to give owners maximum control over their dogs quickly. Owners snap the choke collar to gain their dog's attention, and release it quickly to stop discomfort. Prong collars only apply pressure where the prongs push into the dog's neck. Although they look more torturous, prong collars may actually be safer for your dog's trachea and spine than regular choke collars. Used and fitted properly, either may help an owner gain control over a wild or unruly dog with little danger of physical harm. But control is forced upon the dog more than behavior is encouraged. Carefully consider how using choke chains or prong collars fits in with your overall training strategy before using them on your dog.
Head collars or head halters such as the Gentle Leader or Figure 8 Collar are another training equipment option. They fit over your dog's head, and the leash is attached underneath its muzzle. They work by controlling the directional movement of the dog's head. Once the direction of the head is controlled, the body follows. Like choke and prong collars, they raise concerns about forcing behavior and potentially creating resistance.
Pugss respond best to training that builds mutual respect between themselves and their owner. Most prefer to choose to behave, rather than being forced into submission. Dogs respond to training collars and harnesses differently, and you should never force your dog to use training equipment it does not respond well to. Should you decide on a specially designed training collar or harness, be certain you know how to use it, and fit your dog appropriately.
Consider them stepping stones, or temporary fixes to control or safety issues, rather than lifelong training solutions. Stay focused on the long-term goal, which is teaching your dog to be a happy, enthusiastic learner.