Silca Mattone seat packs use the power of BOA® to keep all your spares in a compact, rattle free pack. A high friction Hypalon strap with BOA® Closure completes the package. Making more than 15x the power of Velcro®, the BOA® Closure uses a ratcheting mechanism that will not creep or loosen even under the most extreme vibration and impact. This ensures the Mattone will remain 'high and tight' under your saddle until you need to access it. no swinging, swaying, or rattling.