Train up to three dogs on your Delta or Delta Sport device by adding more collars to your pack. These compact, waterproof (IPX7 standard) and rugged devices have integrated stainless steel contact points optimized for all dog breeds and all coat lengths. Innovative BarkLimiter™ corrects unwanted barking through advanced bark-correction technology (works with Delta Sport only). Collars are powered by long-lasting rechargeable lithium-ion batteries (included) for up to three months per charge. Compatible with all Garmin 3/4" collar straps. Includes 3/4" collar strap, charging clip, USB cable and AC charging adapter.