Kit includes an assortment of 60, 80 and 120 grit cartridge rolls for cleaning and modifying intake and exhaust ports to match gaskets, remove casting marks and for smoothing out runners. Two 1/4 mandrels are included with each kit. Allstar Performance ALL11052 Cylinder Head Porting Kit – Case/Mandrels/Rolls – Universal. ATV, UTV, Motorcycle & Marine. Audio & Mobile Electronics. Books, Literature & Videos. Engine & Engine Components. Lifestyle, Clothing & Memorabilia. Oil, Fluids, & Chemicals. Tools & Shop Equipment. Trailer, Towing & Winches.