RX-120 Large ReceiverThe RX 120 Large Receiver is an outstanding choice for training dogs that are particularly stubborn or highly driven by prey, due to its robust design and adaptability to diverse training environments. Whether you are looking to replace a lost or damaged receiver or wish to expand your 1 Dog system to include an additional dog, this receiver serves as a versatile solution. Replacement collar for the Boss and the Upland models. With standard one inch