The link is to the company that makes biothane. Biothane is nylon webbing encased in polyurethane. That makes it waterproof and because it is waterproof it does not retain odour. And is much easier to keep clean. It is also said to be less itchy since it dries quicker than regular nylon collars. It is very, very strong, yet flexible, and used a lot in horse tack these days. You have probably seen those dayglo orange collars used on hunting dogs, they are biothane.