Bolt Shd .38-16 X . 9X39MA

The Shoulder Bolt (size: 3/8 16 x 3/4) is a black, metal, individually sold part. It can be installed using a wrench or socket. This part is used to secure other parts in place. You'll know if it needs to be replaced if the part is coming loose. This means it is damaged, likely due to fatigue/wear/damage. Refer to your make, model and diagrams to ensure you're picking the right part.