It's a strap. But do you need it?
The Klimb has no pre-drilled or tapped screws. So you need to ***** self tapping screws in yourself through the plastic. You're basically buying $1 worth of elastic and 3 self tapping screws here. It does what it says it does, can't complain. But I never even installed it because the legs snap in so securely anyway there wasn't really a point.