Checkline YSL2000HD [YSL-2000HD] Yarn Meter Tachometer, Range Non-Contact 1.00 - 99,999 Rpm / Contact 1.00 - 19,999 Rpm. The CHECK-LINE YSL-2000HD (A5-1200) combines the functions of three separate instruments in one, easy-to-use device. It accurately measures the speed and length of yarns, and other filaments using a unique "wrapper" roller. This precision roller directs the filament onto the low-inertia, U-grooved measuring wheel to maximize contact and eliminate filament slip and breakage. The YSL-2000HD can also be used as either a contact or non-contact tachometer to measure rotational speeds of shafts, motors, pulleys, etc. or linear speeds of moving surfaces such as conveyor belts, webs of paper or fabric, etc.