10PCS Universal Whatproof Permanent Car Motorcycle Tyre Tread Rubber Paint Marker Pen + Free Shipping Length:about145mm/5.7",Diameter15mm TipDiameter:Approx.4.5mm Shake several times,Press the tip down 3 or 4 times Canbewrittenonanysurface metal,glass,wood,plastic,paintedsurfaces,etc.