1."S" SIZE: 24" length, totally 4 size from 16" to 40" inchs for Small, Medium, Large, and X-Large dogs.suitable for many kinds of pets with different weight, please measure from your dog's harness clip to your car's latch bar to determine best size.we believe all your request will be satisfied. 2.FEATURE: Double seat belt attachment design,you can connect it to your car's regular seat belt with the nap OR you can connect it to latch bar in your cars back seat creases.so the passager and your pet can use the seat belt in the same time without influence. 3.MARTERIAL: Our dog seat belt is made out of heavy duty plastic coated stainless steel rope, the same material used in dog tie-outs.it is indestructible and durable. 4.PREVENTS DISTRACTIONS AND AVOIDS DANGER: has a tested tensile strength of 200 lbs, it can restrain your dog's active space in the car,allowing your dog to freely sit,stand and lay down without distracting 5.APPLICATION: not only can be used in your car as Safety Seatbelt Leash/NO-chew resistant for dog,but also can be used as double leash or jogging leash for men or women