The DT-2236A is a high-precision optical/contact tachometer suitable for a variety of speed measurement needs. Key features include: Optical and contact measurement methods for flexible application scenarios. High-precision measurements ensure accurate results. Multiple speed unit options, including RPM, m/min, and ft/min. Clear LCD display for easy data reading. Automatic range selection improves measurement accuracy. Maximum/minimum value recording for tracking changes. Automatic shut-off feature to extend battery life.