This is the Acer Racing Ceramic Nitride Pro Series Bearing Kit for the HPI Vorza. FEATURES: Assembled with diamond polished super lightweight Ceramic Nitride Balls which do not deform under load and also insure low friction and low heat buildup Over 33% less bearing friction compared to conventional bearings Exclusive no contact seals for the lowest friction and best dirt resistance Lightly oiled with Acer"s SIN synthetic oil that creates an ionic bond between the oil and bearing parts for silky frictionless action INCLUDES: Fourteen 8x16x5mm bearings Four 8x14x4mm bearings Four 6x10x3mm bearings REQUIRES: Installation following the model manual ajw11/23/2010 ir/jxs