Holt Head Collar - Black Just fit, fasten and walk. Conveniently labeled to use in three easy steps, the Holt walking collar provides gentle guidance to stop dogs from pulling while walking. The Holt features a padded nose band for comfort and an adjustable camlock for the perfect fit, while still allowing the dog to pant and drink water. Size: 0 (for dogs up to 10 lbs) Size: 1 (for dogs 10-20 lbs) Size: 2 (for dogs 20-45 lbs) Size: 3 (for dogs 40-70 lbs) Size: 4 (for dogs 64-100 lbs) Size: 5 (for dogs 90+ lbs)