DT Systems 2090 Ultra Min-e No Bark Trainer Adjustable collar fits dog's neck sizes from 6 1/2" to 24"; collar box is compact, lightweight, and waterproof, it measures approximately 1 1/4" x 1 7/8" and weighs just under 4 ounces Vibration sensor only picks up vocal cord vibrations eliminating unnecessary "shock" from extraneous noises or dog's tags; automatic three second safety delay 8 intensity levels; digital memory remembers last level used Patent pending magnetic on/off system with built in magnet on collar clip; no more lost magnets like other brands Stimulation tester, longer contacts and sensor, and first battery are included (replaceable 6-volt alkaline or lithium battery) Adjustable collar fits extra small to extra large dogs Delivers 1/2 second corrective stimulation 8 different intensity levels Data memory system saves last used intensity setting