1、The product has built-in inductor, equipped with magnetic switch. 2、The built-in buzzer can produce 8 different "BIB" sounds. 3、It is placed around the dog's neck and produces a short "BIB" sound when the dog moves quickly​. 4、When the dog moves slowly or does not move, it indicates that the dog has found the prey. At this time, the product will make a continuous "BIB" sound.​ 5、"BIB" is the first dog, two "BIB" means the second dog, and so on, the hunter can control eight dogs at the same time. Features: The product has built-in inductor, equipped with magnetic switch. The built-in buzzer can produce 8 different "BIB" sounds. It is placed around the dog's neck and produces a short "BIB" sound when the dog moves quickly. When the dog moves slowly or does not move, it indicates that the dog has found the prey. At this time, the product will make a continuous "BIB" sound. "BIB" is the first dog, two"BIB" means the second dog, and so on, the hunter can control eight dogs at the same time. Specification: Condition: 100% New Material: plastic Color: yellow Size: approx.12*11*3cm/4.7*4.3*1.2in Weight: Approx. 295g Package List: 1 x Beeper Collar 1 x Training Collar 1 x Screwdriver 1 x Magnetic Switch