TACHOMETER The HT-4200 is a compact, non-contact type handheld digital tachometer. Affix one of the reflective marks to the rotating surface of the target measurement object, and then aim the red visible ray at the mark. If multiple marks are affixed to the target of measurement object, measurement can be performed at a lower speed.   Features The 5-digit display enables wide-ranging measurement from 4 r/min (when multiple reflective marks are used.) to 50,000 r/min (when single reflective mark is used.) A large-size display device (10.5-mm character height) is incorporated into the compact, lightweight device which can be easily slipped into your shirt pocket. Built-in convenient memory function for easy confirmation of the measured results Even shiny shafts can be measured by using the reflective marks provided with the device. Measurement can be performed over a wide range from 30 r/min to 50,000 r/min, in 1-r/min resolution (when one reflective mark is used). Measurement can be performed safely at a distance ranging from 20 to 300 mm between the detection unit and the target measurement surface (the reflective mark surface). The latest measurement value continues to be displayed for approximately 30 seconds even after the power has been switched off. Battery replacement time indicator is provided.   Specifications Detection method Red visible ray photoelectric reflection method Detection distance 20 to 300 mm Display 5-digit LCD (10.5-mm character height), fixed measurement unit (r/min) Measurement update time 1-s automatic update (2-s update when the circumferential speed is lower than 60/number of reflective marks r/min)   Accessories Reflective marks 1 sheet (25 marks) AAA-type batteries 3 pieces User’s manual 1 copy