The 8341-UHV Ultra-High Vacuum Rotating Picomotor Actuator is for those vacuum applications (10^-9 Torr) requiring rotation without translation. This 0.0187 in. (4.76-mm) rotating shaft is ideal for rotating small optical components or mechanical devices from remote locations. The 0.375 in. (9.5-mm) diameter shank lets you mount the Model 8341-UHV just like our other actuators. A convenient flat on the end of the shaft allow solid coupling to external components. Note: the lifetime of the rotating shaft is 15,000 cycles.