The Fletcher-Terry ScoreMaster II System features a generous reservoir and unique flow valve within the glass cutter which dispenses the precise amount of fluid for a perfect, smooth score. Tests show that you can score more than 1000 feet of glass on one fill-up. (If you get bored some evening, you might try to check this statistic. It sounds exciting.) The patented valve system resists leaking and provides a fine bead of oil only when you apply pressure for smooth cutting. Air is vented automatically. For optimum cutting performance a mixture of 50% light machine oil and 50% kersosene is recommended. For added flexibility, the ScoreMaster System is engineered to provide the option of fixed or swivel head cutting. The fluid-dispensing ScoreMaster glass cutters have a contour designed handle with a universal grip that fits the hand comfortably and lets you cut with a pull or push stroke. They have a no-roll feature and tapping ball. Each ScoreMaster comes with a Tungsten Carbide 134 degree small wheel for general purpose oil cutting. For cutting various thicknesses or textures of glass the system accommodates the three interchangeable heads shown below. Scoremaster provides the ultimate in smooth scoring without flaking.