The most popular RPM wheel, the Revolver, is now available in a Short Course version (2.2" - 3.0"). RPM Revolver Short Course wheels are built tough, like all RPM products, look incredible, and have an all-new drive system that is built to withstand some serious power.The RPM "Spline Drive" system is radically different than the standard hex drive. A hex is easy to machine and easy to manufacture, which is why it is so commonly used. However, splines are tougher and stronger, which is why they're used in full-sized driveline components. All standard hex style adapters push out and up every time rotational force is applied to the adapter, which is a huge reason why so many hex-style adapters spinch RPM Spline Drives direct the rotational force of the axle in a near perpendicular direction, making the likelihood of a spun adapter virtually non-existent!Additionally, the Spline Drive has almost twice the amount of drive surface area versus a standard 12mm hex adapter and over 2.5 times the thickness at the most critical drive point of the adapter, the point that, if it fails, a standard hex adapter will spinchRPM Revolver Short Course wheels are sold in pairs (spline drive adapters are included in each package), and backed by RPM's industry-leading breakage warranty for unsurpassed strength and durability.