Small Command Collar:

Maximum length (with all extra links added) = 18 ½” (469.9 millimeters)
Minimum length (with max. number of existing links removed) = 5 ½” (139.7 millimeters)

Suitable for tiny dogs such as the Chihuahua, Yorkshire Terrier and Toy Poodle, to medium size breeds such as the Cocker Spaniel, Jack Russell Terrier, and Beagle. It is also useful for brand new larger breed puppies, for the first weeks of their training.

Note: Despite the minimum size of the small Command Collar®, this collar should still fit dogs/puppies with smaller necks; the collar will be a little looser than normal, but it will still be very effective.

Large Command Collar:

Maximum length (with all extra links added) = 24″ (609 millimeters)
Minimum length (with max. number of existing links removed) = 7″ (177.7 millimeters)

Suitable for large to extra large breeds (older puppies and adult age) such as the Labrador Retriever, German Shepherd, Rottweiler and Great Dane.

Refer to Question 1 under FAQs for more information on collar sizing