28255 Features: -Twist drills. -With natural diamond dust for cleaning out holes in pearls, coral, turquoise and other precious stones. -Shank size: 0.93". Number Of Bits: -2. Unit Material: -Steel. Use: -Drill Bits. Generic Dimensions: -Overall dimensions: 0.39" H x 3.54" W x 3.14" D, 0.2 lbs. Dimensions: Overall Product Weight: -0.2 Pounds.