Spectrol 552 servo 1K (now Vishay) high precision servo as used in the aircraft industry, high linearity +/- 0.25%, superb sealed construction. 3 turn suitable for use as a position indicator for motor / hydraulic powered parts shaft size: 7.8mm long x 3.13mm diameter. main body size: approx 28mm long x 22mm diameter excluding shaft and three solder tags. RoHS compliant : tbc