Safety Belt Comfort is a seat belt adjuster that holds the shoulder belt securely so the creep that causes rubbing on the neck and chest from the movement of the car is stopped.The product acts like a Chinese Finger Trap. The more pressure on it the firmer it holds. It was safety tested.What keeping the shoulder belt from moving means to you is your safety is enhanced should a crash occur. You are now wearing your belts as manufacturers suggest, tight on your lap, firm on your chest and on your shoulder bone. You are kept tight against your seat. Holding you firm against your seat means your head does not go into the airbag as it would if your shoulder belt had slack in it or was not across your chest.