The Series of these cutters are comfortable to hold and easy to use, each cutter is self-oiling (when pressure is applied) for a free rolling wheel and consistent score line. The wheel is made of durable carbide steel that outlasts conventional cutters. Cutter heads are replaceable.The Comfort Grip Super cutter is lightweight and the slightly smaller handle makes it easy to hold. The lightweight clear acrylic grip lets you see how much oil is in the reservoir.ZUOS Uses the Super cutter to Cut Thousands of Sheets of Glass without Changing Heads!