... :2008 5.inspection & warranty Namecarbon steel ball for curtainSize1/4",3/16",6mm.6.33mm,6.5mmGradeG1000Quality ... , excellent surface, best quality and high hardnessApplicationMainly used for simply bearing, curtains, castor wheel, bicycle, aviation ... Co., LtdWe have handed various kinds of steel balls for more than ten years and we are reputated ... are welcome! G1000 soft carbon steel balls for curtain