Pool Balls - All balls must be composed of cast phenolic resin plastic and measure 2¼ (+.005) inches [5.715 cm (+ .127 mm)] in diameter and weigh 5½ to 6oz [156 to 170 grams]. Balls should be unpolished, and should also not be waxed. Balls should be cleaned with a towel or cloth free of dirt and dust, and may also be washed with soap and water. Balls contaminated with any slippery substance - treated with polishing or rubbing compound and/or waxed - must be cleansed and dewaxed with a clean cloth moistened with diluted alcohol before play.
A complete set of pool balls consists of one white cue ball and fifteen color-coded, numbered object balls. The object balls are clearly and highly visibly numbered 1 through 15. Each object ball has its number printed twice, opposite each other, one of the two numbers upside down, black on a white round background. The object balls numbered 1 through 8 have solid colors as follows: 1=yellow, 2=blue, 3=red, 4=purple, 5=orange, 6=green, 7=maroon, and 8=black. The object balls numbered 9 through 15 are white with a centered band of color as follows: 9=yellow, 10=blue, 11=red, 12=purple, 13=orange, 14=green, 15=maroon.
The two printed numbers 6 and 9 are underscored