EXPANDABILITY: The EDGE is expandable up to 4 dogs and the unique receiver design offers advanced technology that come in several different colors (black, orange, green, and blue). The Beacon & Locate LED Light also comes in 4 selectable colors (white, red, blue, and green). 1-MILE RANGE: With a range of 1 mile, you won’t have to worry about losing track of your 4-legged companion. This receiver is built with a Beacon & Locate LED Light that can be activated for the light-tracking mode. DOG SIZING: This e-collar is perfect for dogs that are 35 lbs. or larger. With a high output and the ability to expand to 4 dogs, you’ll be able to train multiple dogs at once during obedience training. IPX9K WATERPROOF CERTIFIED: The EDGE receiver is IPX9K waterproof certified, which means it passed the International Protection Marking system. Products are verified if they can stand a close-range high-pressure liquid spray from 4 angles (pressure of 80-100 bars and a temperature of 176°F). CORRECTIONS: This e-collar has two different correction types. The first correction type is a Nick (quick ½-second) and the second correction type is a Constant (up to 12 seconds). The receiver also has a Pager vibration, which offers a clear vibration to alert dogs while training. Find the right fit for you and your dog with this dynamic e-collar.