ROBART Control Surface Deflection Meter

This Is An SDI Gauge (Surface area Deflection Indication) from Robart.

FEATURES:
An essential tool used to determine the quantity of up and down or left
    and right on your model airplane elevator, ailerons, flaps, and
    rudder.
Precise measurement of surface area deflection in INCHES.
Measurement is in 1/16th increments, with 1/4,1/2,3/4 & 1" marked.
Fits big and small scale model airplane.
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No more mistakes with rulers and scales.
Quick and simple surface area adjustments.
Allows for accurate differential adjustments.
Instructions are provided.

INCLUDES:
One SDI Gauge

NEEDS:
Constructed and Decorated Airplane
Radio
Tape
Straight Pin