Dogtra ARC-X 1-Dog UnitMedium power output (1 100) For dogs 15 lbs+ 3 Dog expandable Boost & level lock Compatible with Handsfree Squares Slim fit 30% slimmer than 1900X Nick, continuous & XPP vibration 3 4 mile range IPX9K waterproof Audible tone LED E Collar flashing light [split] Introducing ARC X. Designed 30% slimmer than the 1900X, with Dogtra's proprietary ergo curve that contours naturally to your dog. At just 2. 75 oz, it's so light your dog will forget it's there.