The Dogtra 1900S HANDSFREE PLUS now features a Dogtra HANDSFREE SQUARE, which allows you to control a transmitter discreetly and remotely. You can instantly access different functions at your fingertips and use the 1900S HANDSFREE PLUS for a diverse range of training scenarios. Each HANDSFREE SQUARE can be paired to different functions and allows many users to access any feature, at any time within 33 feet of the transmitter. A replaceable coin lithium CR2032 battery is included. With comfort and safety in mind, the 1900S HANDSFREE PLUS features an ergonomic receiver shaped to the dog’s neck. It has an IPX9K waterproof rating which makes the 1900S HANDSFREE PLUS ready for the most demanding training conditions.