I wanted a muzzle for my staffie that didn't make him look like Hannibal Lector, and found this one. Very pleased with it, looks sturdy enough, and Size 3 is perfect for a Staffordshire Bull Terrier's snout.
Don't put it on your dog straight away or he'll throw a fit trying to get it off. It'll take a few days to get him used to it, so patience is required. Hold the muzzle in your hand and feed him treats through it, so he has to put his head inside the muzzle to get the treat. When he's comfortable doing that (it'll take a while), start putting the straps behind his head for a few seconds at a time, then treat. When he's comfortable with that, then do the strap up for a few seconds, treat, and gradually lengthen the time the strap's on.