Designed for comfort, durability and performance, Studio Pro high quality glass tools and accessories are an excellent value and will quickly become a favorite for any stained glass project. This self lubricating carbide pencil grip glass cutter gives the user the feel of a thick brass barrel cutter but at a fraction of the weight. Strong, lightweight, textured acrylic barrel provides an improved grip while scoring. Cutter heads are replaceable. Specification: Length: 170 mm Weight: 35g Wheel Material: Tungsten Carbide, RL01, rigidity of 94.5, anti-bend 1550 mpa Handle Material: Sturdy Plastic How To Use Glass Cutter: To fill the cutter with oil, remove the plug on one end of the handle, use the bulb syringe to extract oil then deposit them into the reservoir. Replace the plug. Put the glass on a flat surface, wipe clean the glass where you want to cut with a clean cloth. Hold glass cutter firmly in one hand, with your other hand holding the glass. Maintain the same pressure through out the score. Don't let up on the pressure until you have rolled the cutter. Oil will be emitted as you work. When the line has been scribed, gently tap the glass underneath the line (on the opposite side of the glass) with the handle of the cutting tool, and the glass will break along the line neatly. It's better to try this a couple of times on a scrap piece of glass for practice and confidence.