Checkline DT-105A-12CBL Hand-Held Tachometer / Cable Speed Meter - LCD Display. The DT-105A-12CBL is designed to measure elevator cable speed in feet per minute, meters per minute and other measuring units. It is supplied with a rugged 12” circumference wheel with large flanges to keep the cable in contact with the surface. Delivering superior performance and accuracy over more conventional flat surface wheels. Employing a non slip rubber contact surface, the wheel adds safety and accuracy while measuring speeds on Elevator governor cables, wire and cable reels, extruded tubing and many other applications