Motion Pro 08-0537 Valve Stem Seal Install Tool Set - 4 Piece Four common sizes for use on most modern off-road motorcycles as well as ATVs: 4, 4.5, 5 and 5.5 millimeter Properly aligns valve stem seal to valve guide so seal snaps on straight every time while the rounded tip will not damage inner lip of valve stem seal or valve guide bore Holds four valve guide seals at one time for quick and easy installation on multi valve cylinders Contoured design in bottom of handle cradles and protects the delicate inner lip of the valve stem seal while directing tool force to the sturdy outer rim Slim profile allows easy access to valve guides even on modern compact heads with deep lifter bores, anodized aluminum handles with stainless steel pilot shafts