• Patented design incorporates both a photo and a contact tachometer into one precision instrument
• Ranges: from 0.5 to 20,000 RPM in contact mode; from 5 to 99,999 RPM in photo mode; surface speed from 0.05 to 1,999.9 MPM (0.2 to 6,560 FPM)
• Linear surface speed measurements are 0.2 to 6560 FPM or 0.05 to 1999.9 MPM
• Automatically holds last reading for 5 minutes and recalls min. & max. readings
• Characters on the large 5 digit display reverse direction depending on which measurement mode you are in
• Provides accuracy to 0.05% and permits readings to a resolution of 0.1 rpm in either photo or contact mode

Model No. Mfg. No. Description
HF964 K4010 Photo/Contact Tachometer
HD905 AS-35A Replacement Contact Adapter