The ultra-compact and lightweight design of the D.T. Systems Ultra Min-e 2090 No Bark Dog Training Collar makes it perfect for smaller dogs. The tough red nylon collar strap is easily adjustable from 7" to 27" for dogs approximately 5 lbs. to 20 lbs. The collar is 100% waterproof and can be worn while wet. The Ultra Min-e 2090 has eight user-programmable levels of harmless static stimulation. A magnetic On/Off switch is built into the collar and has an included extra keychain magnet. The technologically-advanced vibration sensor only picks up vocal cord vibrations from your barking dog, and not other loud noises or other barking dogs. This technology paired with an automatic three-second safety delay eliminates unnecessary corrections. The 2090 No Bark Training Collar comes with a 6V battery. The average battery life is 4-6 weeks depending on frequency of use. Mini collar box dimension: 1.8"L x 1.25"W x 1.3"H. Mini collar box weight: 3 oz.