FEATURE: Digital display -- The digital tube shows the gears of vibration ,shock and sensitivity. Adjustable mode -- 1-7 level adjustable sensitivity, 0-7 gears of the vibration/shock, you can choose according to the instructions or the actual needs of your pet. Automatic protection -- an automatic protection mode to deactivate the collar if activated 7 times in 1 minute then back to work in one minutes. Adjustable Reflective Strip -- That allows you to keep an eye on your pet even in low visibility and also can protects your pet life from cars etc. Testing 1.Turn on the power.2.Set the sensitivity to 5-7grade and the shock greater than 0 grade.3.Wear the tester on the conductive silicone prongs behind collar.4.Please send a short voice like ?wow? (as short as possible) to sensors.Since the frequency of human voice is different from that of pet,please test more time.Specifications: Item Size: 2.6 X 1.5 X 1 inchesItem weight: 70gPackage weight: 120gCollar Perimeter Size: 7.4-23.5inchesPackage Includes: 1 x No bark receiver1 x Adjustable Nylon Collar1 x Test Light1 x USB Link1 x InstructionNOTE: 1, Charge it before first use (adapter less than 1A). 2, If you need to adjust the strap and cut the redundant part of it, heat the end of the strap with a lighter, in case it get a raw edge. 3, Don?t wear it exceeding 10 hours a day, or it may affect the dog's skin. 4, Don?t let the dog alone at first several times. 5, Check the tightness of the strap and your pet skin regularly.The prongs must be against your pet skin to work,you just can fit one fingers snuggle between the neck and collar.6, Please take off your iron collar,before you put the bark collar??????????