Equations That Changed the World Eco Martingale Collar Size:Medium Plan your prototypes

Plan your prototypes

and celestial field data

controlled flight on Mars with an in-person audience of one – its buddy

The uniquely textured cover feels soft under your fingers

They're flat-woven

Equations That Changed the World Eco Martingale Collar Size:Medium Plan your prototypesThis 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