BioThane® is the brand name of all coated webbing products made by BioThane Coated Webbing Corp. It's basically a polyester webbing with a TPU or PVC coating that makes it more durable, waterproof, easy to clean.

UV stable, so will not fade. 

We use 16mm wide Bio-Thane to make Dog training lines, leads and can be used by Horses for Lunge lines, Long Reining and lead ropes. Combined with strong Nickle plated steel snap hooks and strong Chicago screws instead of inferior rivets for extra protection.

Just like nylon, rope, webbing, or leather, bio-thane is not chew proof and a determined dog will be able to damage or even chew all the way through the line. For this and other safety reasons, you should never leave your dog unattended wearing any leash or long line.