The Halo Collar is an electronic unit that comes in one size and attaches to a strap. With the new Halo 4, there's no more guessing with the single size strap. Whether your dog is big or small, the tailoring system lets you custom-fit the collar to your dog’s exact neck size, ranging from 8 inches to 30.5 inches. Each Halo Kit comes with a Perfect Fit system, ensuring a comfortable fit for your dog regardless of breed!

If you have a growing dog, you can easily adjust the strap to grow along with them. Please note that we recommend your pup be at least 5 months old before starting training with the Halo Collar. 

Here is an instructional video with more information.

If you have any further questions and would like to speak to our live support team, please feel free to reach out using the following article: How to Contact Customer Support and we'll be happy to help!