Quick and easy way to convert your Stan's rear 3.30 HD hub to the new All Mountain 12x142mm thru-axle standard. Installation requires you to remove the existing end caps and then pop these in. It doesn't get much easier than that. The caps are constructed from light alloy that is black anodized to add strength and match the 3.30 HD hub cosmetics. These only work on the HD hub commonly found on the Flow and Flow EX rear wheel. They are not compatible with the standard 3.30 hub.