Equations That Changed the World Eco Martingale Collar

This math-inspired collar is great for accessorizing your favorite fuzzy friend while you work on your problem sets.

Martingale collars are what you need if your dog's head is smaller than its neck – like a greyhound or a whippet, any dog prone to slipping their collar, or dogs with delicate tracheas and necks – like chihuahuas and pomeranians.

Our Martingale collars are available in three sizes, adjustable, and built with rPET webbing (made from recycled soda bottles).