.carbon steel tube with chrome plated.punched round hole.sliding card packing / in pvc pouch.size 6pcs: 8*9, 10*11, 12*13, 14*15, 16*17mm 10pcs: 6*7, 8*9, 10*11, 12*13, 14*15 16*17, 18*19, 20*22mm