Principles of operation: At the first bark,collar applies a short warning tone. If a second bark occurs within thirty seconds,a more intense tone is sounded. From the third bark,a more intense tone is sounded along with a short,mild shock. This pattern is repeated through 7 correction levels.The first two levels are only with progressively warning tone.If your dog continues to bark through the rest five levels,the more intense sound and shock are applies after each bark until your pet stops for thirty seconds,and the Anti-Bark Collar will automatically resets to the first"Tone only"level of correction.To protect the dog,if the continuous stimulus reaches the 7 levels,then the collar will stop working for 1 minutes. Feature: Easy and convenient to test the functionality and sensitivity by blowing. Indinite sensitivity adjustable by gear to suit for different dogs. 2 training modes: beeper and static shock. 7 levels of sensitivity adjustment by "+" and "-" buttons, to be suitable for different dogs. 7 different combinations of beeper and static shock to train dogs effectively The collar turns into 1-minute-automatic protection mode after 7 times consecutive working. Adjustable leather leash from 6" to 30" to suit for different dogs: small, medium and large. Product Attributes: Material:PVC Color:As the picture shown Quantity: 1 Pcs Size: 7.8X3.4X3.8CM Package Include: 1 x Bark Stop Controller 1 x Adjustable Strap 2 Pairs of Test probe 1 x Test light 1 x 6V alkaline battery 1 X English Manual Note: 1.Due to the light and screen difference, the item's color may be slightly different from the pictures. Please understand. Make sure you don't mind before you bid. 2.Please allow 1-5mm differences due to manual measurement.