VSI, 3 1/8", 0-4000 fpm, TSO

United Instruments vertical speed indicator (VSI) measures change in static pressure to provide accurate and reliable indication of rate of change in altitude in feet per minute. Zero is at 9 o'clock position with zero adjustment screw at 7 o'clock. 3-1/8 Instrument round with 1/8-27 ANPT static port on rear. Meets FAA TSO C8b.