The Halo Collar strap comes in 2 sizes, suitable for dogs 5 months and older, 20 lbs or more (9.1 kg or more), and with neck sizes between 11 " and 30.5" (27.9 cm and 77.5 cm).

To measure your dog's strap size, follow the instructions in the image below. 

Collar Strap Measurements: 

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!