Finally a training collar that will work on the most stubborn dog. A standard 21" (3mm link diameter) and 24" (4mm link diameter) chrome-plated pinch collar designed for quick-release by way of the Ray Allen Logo metal buckle. Quick-release buckle connects to high-quality pinch links by 5/8" tubular nylon bands. Strong nickel-plated D-ring for lead attachment. Buckle color may vary. 21" Collar available in Black, Blue, Red, Purple or Pink. Additional links are available for both 3mm (HS91301).