Transmitter slides into pouch and attaches to halter’s connecting strap (strap under jaw connecting noseband to throatlatch). Pouch is made of durable material and attaches easily to halter. New Pouch fits NEW smaller Transmitter - only 2 5/8" x 1 5/8" x .5". Please note, all Transmitters ordered are supplied with new pouch. You can order additional pouches if pouch has been misplaced, damaged or you want to have extra on hand.