Hobbico Digital Mini-Tach is the perfect addition to any flier's Field Box.
  This Digital Mini-Tach allows you to accurately monitor engine performance
  and evaluate the effects of different fuel and props to improve your model's
  performance.

FEATURES: Durable ergonomically-designed, durable Black case with rubber bumper
            strip increases ease of use and durability.
          Includes two pre-installed "AAA" batteries
          AUTO-OFF after 5 minutes if idle
          One-touch switch operation with a protective ring that prevents
            accidentally switching the unit ON in the Field Box
          Operating range 0-32,000 RPM
          Measures 2 and 3 bladed props (not 4)
          Can be used up to 12" away from propeller
          Large easy-to-read .5" (12.7mm) LCD display
          One Year Limited Warranty

INCLUDES: One LCD Digital Mini-Tachometer
REQUIRES: Nothing, AAA batteries are included

SPECS:    Length: 3¾"
          Width:  2½"

COMMENTS: Hold tach 4 to 12" away from propeller
          Use "AAA" alkaline batteries for replacement when necessary
          This Tachometer uses a sensitive photocell to measure the number of
            times propeller blade crosses between the sensor and sunlight.
            If readings become erratic, change the direction the model is
            facing by 90° and take another reading. Do not use indoors as the
            reading will not be accurate.
          Instructions are on the box
                                                                       KLH12/99
                                                                          ir/jl