Herm Sprenger Black Stainless Steel 16" Prong Collar, One Size Herm Sprenger 50055 | Prong Training Collar | Anodized Black Stainless Steel | (10) 2.25 mm Prong Links | Made in Germany. Center plate assembly from which five (5) prong links are assembled on both side of center plate with prongs links placed directionally toward buckle | Easy release snap buckle with D-Ring for lead attachment. Initial purchase 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/removed to adjust fit | Additional prong links can be purchased separately. Read Product Description for additional instructions for sizing, fit, and care.