The 4' Mini Tow Scarifier is a heavy-duty tow scarifier that is truly a workhorse for reconditioning compacted clay courts. This unit is heavy enough to allow its three rows of case-hardened nails to penetrate the surface. The nails are staggered on each row to prevent clumps and sized to fit between the alley tapes. Levered wheels lift the unit over tapes so that tapes can be left in place during scarification. The case hardened nails are angled and actually self sharpen as they are used. You can adjust the steel rails to lower nails as they wear. The steel nail plate is removable for easy nail replacement.