This angle of attack instrument is designed for experimental aircraft pilots. Angle-of-Attack unlocks Navy carrier pilots secrets and puts a priority on safety. All approaches should be flown at the same optimum approach angle of attack not the same IAS. We can now do precision approaches just like the military and airline pilots and accurately gauge Vx, Vy, Best glide, L/D max, and maximum endurance AOAbecause angle of attack is not a function of weight, bank angle, fuel load, density altitude and etc. This revolutionary angle of attack instrument is based on a long known aerodynamic principle. The AOA Professional includes a four color liquid crystal display and a aural voice system which warns of critically high AOA, gear position errors and installation/hardware errors. There are no ugly probes, vanes or protrusions to slow you down or accumulate ice.