Review on Herm Sprenger Black Stainless Steel Prong Dog Training Collar: No-Pull German-Made Swivel Ultra-Plus Pet Pinch Collar for Effective Anti-Pull Training by Kristen Simpson

I ended up buying both sizes because my dog's neck was right at the 16" mark and I wasn't sure if I wanted to go bigger or smaller should go. The 16 in one is right up her size but the tines are a bit small for her but still very effective. The 21" has a lot more lugs so the fit isn't as precise but it still works well. I use the tine when we run because she can run a lot faster than me and it helps her move, but if your pup needs some corrections I would definitely recommend this tine, it is very well made and the teeth are not sharp at all like some of the cheaper models.