Sigma-Tek Vacuum Attitude Indicator 5000M-1. Finally! An air driven attitude indicator 23-501-035-5 with caging feature provides quick erection when needed after short stops or after aerobatic maneuvers.The Sigma Tek air-operated artificial horizon gyro is selected as standard equipment by aircraft manufacturers worldwide. The Sigma-Tek Vacuum Attitude Indicator 5000M-1 artificial horizon displays aircraft attitude through 360 degrees in pitch. Its pictorial presentation gives faster interpretation of airplane attitude with blue for sky and brown for ground. Pictorial airplane remains fixed during gyro operation, adjustable to compensate for changing conditions. Case mounted Inclinometer, internal lighting and eight degree tilt are available. Also available with warning flag to alert pilot to loss of pneumatic power.