This clever guide keeps your shoulder strap properly positioned over your shoulder instead of chafing against your neck -- or even falling off. It also keeps your strap ready to grab when entering the car. Furthermore, it eliminates those twisted and tangled seat belts. Made of tough but flexible black plastic with UV inhibitors for long life. Installs by removing your head rest and simply sliding on for a friction fit. No tools required. Guide can also be modified for snap-on installation if your head rest is frozen. Fits all single-post headrests. Sold by the pair.