The Spider Cutter from General Pipe Cleaners has front and rear blades, so cutting starts as the cable feeds into the line and continues as it retracts. The Double U-Cutter and the Double Heavy Duty Side Cutter each come in 3- and 4-inch sizes. Double U-Cutters can also be adapted to sectional machines, or to other brands of cable-type drain cleaners. 800/245-6200; www.drainbrain.com.