Wasn't sure I needed a four-pack until I misplaced one key mid-trip and had three spares sitting in the glovebox. They fit the rack bolts snugly with no wobble, and the 5/16 size is exactly right for my accessories.
Victoria U.★★★★★
Lost the original key for my roof rack mounts, and this four-pack got me sorted right away. The 5/16" size fits the hex bolts snugly with no wobble, so I've got spares stashed in the glovebox now.
George K.★★★★☆
The 5/16" size fits my roof rack bolts perfectly, and having four in the pack means I've stashed spares in the glove box and toolbox. Only gripe is the keys are a bit short, so leverage on stubborn bolts takes some effort.