Sigmatek 3-1/8 Airspeed 40-300MPH 40-200KNT

These airspeed indicators have unrestrained movements.These instruments are actuated by ram air and ambient atmospheric pressure obtained from the aircraft pitot and static pressure systems. A moveable pointer and a fixed dial indicate airspeed with the zero index at the 12 oclock position. Temperature compensation is internal and there is no external zero adjustment. Pointer damping is internally adjustable.