STX have introduced the "Cell X" range which is specifically targeted at box lacrosse players. The shoulder pads are one of four new items released in this range. The other three being rib pads, arm guards and bicep pads.
This range was introduced to fill a bit of a hole in the market which is specific protection for box players. Of late, there's bit a bit of activity in this space with the release of thicker and stronger box specific lacrosse shafts. If ever you've played both field and box lacrosse you'll know that the protection needs are different. For field you need to guard against the odd wild or well-placed slash. But for box you need to guard against the endless and unrelenting cross checks to all parts of your torso.