One Size: 1'(W) * 16 1/2'-25 1/2'(L) This dog seat belt tether fits most vehicles on the market. However, this is NOT compatible with Volvo cars. Pet owner should always use this product with a HARNESS. Never attach the clip directly to a dog collar. The tether is designed to be clicked into the female slot of your vehicle. Please read instructions on the product carefully before using. This seat belt is a single product. Its matching collar leash and harness available separately. Machine-washable, in cold water on the gentle cycle.