World Champion ACER Racing 1/4x3/8x1/8 Flanged Ceramic Ball Bearing. This is a 1/4x3/8 Flanged ceramic ball bearing also known as a size FR168 ball bearing. Diamond polished Silicon Nitride (Si3N4) Balls, HSR cage technology and sealed on both sides. Lubricated with lightweight and 100% synthetic ACER Racing SIN Oil instead of thick grease for super fast and super smooth action.
