IIRC this was originally made by TruTrak (sold to Bendix-King). Although it looks like an AI it is not. The roll direction is computed by a turn-coordinator type device, while the pitch is computed from vertical speed. e.g., if in a prolonged nose-high slow flight configuration, the instrument will show ‘nose level’, as the vertical speed is zero. The 3 1/8” version had a stall indicator built in, as a precaution against an inadvertent stall while showing ‘nose level’. I think many of these were installed as backup units and/or as autopilot controllers