Works GREAT! So worth it. Safe for your dog. So many educational videos online. Picture included shows 18" collar length since cut. Great for small to medium/large dog. Perfect condition. Collar, charger, etc included. The Educator ET-400 is a low to medium power remote e collar designed for dogs over 5 pounds and boasts a 3/4" mile line-of-sight transmit range. Perfect for dogs that have a bit more room to roam, or areas with dense foliage or varying elevations, that could weaken the signal to the collar. Like all Educator Collars, the ET-400 is crafted with the latest cutting-edge e-collar technologies and offers precise stimulation levels that can be adjusted from 1 to 100 depending on your pet's temperament and level of excitement. It features patented "blunt stimulation" technology that delivers a clean, medical-grade stimulation similar to a TENS machine used on humans to excite muscle to reflex. The ergonomic stopwatch design of the remote control allows you to easily operate it through its tactile buttons without taking your eyes off your dog. The waterproof construction of both the receiver collar and remote transmitter guarantees reliable operation even when submerged in water, and the remote floats. As a safety feature, the powerful remote-controlled night tracking light on the receiver collar keeps your dog safe and visible at night.