Great to have in your field repair kit or to replace an already broken strap. Even if you just need one for replacement it's a good idea to have a backup when you're out on a ride.
These straps are used on the sides of the Backcountry Panniers (V2.1 and newer) to retain the roll-top. Similarly, they're also used on the sides of the Reckless 80 Revolver legs to retain the side drybag roll-tops.
The wrong strap was sent with my R40 bags. Replacement sent with no hassles at all.
Still didn't get this Replacement Swivel Straps. Its 23 days past, and i have no idea will it come for me or not.