Shoulder pads protect a player's shoulder during contact. Some shoulder pads are designed with the neck roll (designed to protect the head from whiplash) and rib pads built together.
How Pads Should Fit
The arch cushion of the shoulder pad should not overlap the A/C joint (Acromial/Clavicular, tip of the shoulder where the clavicle and scapula join) by more than a half inch to one inch for proper fit. Depending on the position of the player, the shell should come down just below the sternum and to the mid-back. The neck opening should fit comfortably and allow for a full range of motion.
Sizing Pads
Measure the width of the back from shoulder joint to shoulder joint while keeping arms relaxed and at the side. See charts below to convert this measurement into the proper shoulder pad for you.