As the name implies Sport Japan discs were originally designed for the Japanese market where tough looks and high performance are important factors. Sport Japan discs are now one of the only aftermarket performance discs to still feature fully drilled countersunk holes which are much more affective at venting gasses which cause brake fade than the more common dimples. 6 grooves on the braking surface keep pads from glazing. All Sport Japan discs are based on original equipment specification, T√úV approved castings, heat treated for strength and hand finished to ensure the smoothest possible braking surface. Sport Japan Discs are T√úV approved for most applications.