The Run Razor / Blocker Set includes: - Run Razor .Gives final touches for a perfect finish shaving down semi-hardened runs, sags or dust between colour and clear coats. Holder takes standard razor blades, set at a precise angle. Pass gently over the surface, dialling down the blade position indicator in .001\" increments until the imperfection is gone. - 3 x Run Blockers . Three differently contoured aluminium blocks to be used with wet/dry paper to block out runs, sags or dust. They can also be used for block sanding body filler or primer in hard-to reach areas. Non-compressible alloy ensures a wave-free finish.