When it comes to choosing a BNS, fit is more important than weight. Both models have a hinge at the back and a clasp at the front. Fit primarily affects how the unit works, but it's also important for comfort because the thin padding on the underside of the collar (so designed to keep the dimensions compact) will not be comfortable if it doesn't contact the neck and shoulder area evenly. The BNS is sold with a stretchy X-strap that can be worn over or under a jersey to hold it in place, or you can order the optional, larger A-strap that fits it tighter to the body. It can also be worn under a chest protector. With the proper fit, I found both BNS models to be comfortable and unobtrusive.