Predominantly a three-tier action, but some with two were made.

The valve section of each tier was usually surrounded by bellows cloth; this was used to seal the joint, rather than the leather gasket. The valve is a wood turning faced with leather and extending beyond the leather washer, the reduced center of the wood turning forms the stem for going through a red fibre strap across a metal valve plate. The outside valve plate is secured with four screws and a blotter paper gasket; the bottom or inside valve plate is sealed with shellac and screws. The wooden pouch button screws into the lower valve stem from the underside of the plate, making it necessary, in retrieving an individual valve, to cut back the front cloth cover on the valve chest in order to grip the pouch button to unscrew the valve from it by turning the top valve stem. The pneumatic motor has three double pneumatics which hinge in the middle with a thin brown leather patch over the hinge.

Although AEolian never produced a Service Manual for this particular action, the stack, air motor, tracking system, air motor governor, action cut-out and peripheral devices are identical to those in the Pianola, Themodist and reproducing Duo-Art actions. These parts were installed in upright and grand player piano made by Steck, Steinway, Stroud, Weber, AEolian, and others. This player action is well covered in Art Reblitz's book "Player Piano Servicing and Rebuilding", which is available - Click Here

AEolian also produced a system called the Technola/Metrograde. It has a two-tier stack and manual control levers for Bass and Treble Soft, which operate a split hammer rail. It has pushbutton controls for operating a Ritardando/Accelerando device that is built into the Tempo/Air motor Governor Control Box. It also has a lever for manually activating the Sustain Pedal as well as a pneumatic device for Automatic Sustain via perforations in the music roll. More detailed information about this system is available 'here'.