The Tusk Sliding Sag Scale is a must-have tool to help you precisely set your motorcycle sag. "Race Sag" is a reference to your rear shock’s ride height with the rider onboard and is critical for performance and safety. This scale is adjustable in length to work on any bike. Simply set the scale to zero with your bike on the stand and quickly see the exact "race sag" with the rider on the bike. The anodized aluminum body with a laser-etched scale is simple to use and very durable. The axle pin will fit hollow axle holes up to 24mm. When in need of quality parts and tools for your dirt bike, ATV or UTV, think Tusk!!!