ENGINE TACHOMETER (PET-2100DX) (OPPAMA) from 1 to 4 cylinders Quick to install and remove, the PET-2100 DX tachometer is at the cutting edge of technology. The processor updates the engine rpm counter 20 times per second and has an accuracy of 10 RPM. Product of the Oppama brand, compatible with watercraft with a 2-stroke engine, 1 to 4 cylinders.