I believe the attachment is correct and useful. It does not cover the gap from the outside, it covers it from the inside. The left side of the collar should be on the outside, and the right side should be tucked inside. The throat attachment extends further inside and is then covering any gap between the collars as it sits over the right collar that is now inside, and under the left collar that is now outside. The strap and buckle allows you to adjust the length so that the "V" of the throat attachment is in the middle of any gap in the collars, based on the size of your neck. It's probably more trouble than it's worth, but would provide some extra protection in severe weather.