Herm Sprenger Stainless Steel Training Collar 2.25 mm with Safety Buckle Canvas Billets D-Ring Herm Sprenger Model 50037 | Prong Training Collar | Stainless Steel | (10) 2.25 mm Prong Links | ClicLock | Canvas billets | D-Ring Center plate assembly from which five (5) prong links are linked on both sides of center plate with prong links placed directional toward center plate. Prong ends are beveled and polished. ClicLock buckle design easy to use by those with compromised hand dexterity. D ring for lead attachment. Manufacturer factory assembled size fits neck size up to approximately 14 to 15 inches depending on fur type and fur depth. Collar opens to approximately 16 inches. Prong links can be added and removed to adjust fit. Additional prong links can be purchased separately Manufacturer recommends this collar for dogs with maximum weight of 20 kilograms or 44 pounds. Manufacturer recommendation for prong size according to dog weight: 2.25 mm for up to 20 kilograms or 44 pounds; 3 mm and 3.2 mm for up to 40 kilograms or 88 pounds; 3.9 and 4 mm for up to 70 kilograms or 154 pounds Read Product Description for additional instructions for sizing, fit, and care. Made in Germany, Herm Sprenger authenticity is verified by the embossed logo on the center plate, specific rings, and junction components