Colour: Blue and Yellow. Safe Bark Control CollarAs pet lovers, we don't want this stop barking collar to cause any harm or trouble to your dog. Collar work only through vibration and sound, no impact. When the machine detects the dog barking, the device will emit a beep warning sound and a weak vibration. If the dog continues to bark, the device will increase the sensitivity level to make the dog realize that the barking is wrong, and your dog will gradually learn to Stop its dog barking 7 Levels Sensitivity Adjustment7 levels of automatic dog barking level sensing, according to different strengths of dog barking, the device will set different sensitivity levels for the sound. As the sensitivity levels increases, the intensity of the vibration increases, warning sound and the duration of the vibration is also lengthened Can Be Charged RepeatedlyThe anti barking collar can be recharged repeatedlyNo need to replace the battery, green, clean and environmentally friendly, saving you time and money. It can be fully charged in about 2-3 hours and has a standby time of up to 60 days Adjustable Collar LengthThe length can be adjusted according to the size of the dog's neck. The length of the collar can be adjusted from 3.94-13.78 inches. Such a small product can be suitable for small to large dogs Easy To Use The bark control collar allows the collar to be used in any weather conditions. It has waterproof performance and can work well even in rainy weather, but it is not recommended for dogs to wear a bark collar to swim