This is a hollow steel Aeroproducts blade, drawing H20H-162-40M5, used in the A422-E1/E2 propellers that pulled the NAA T-28A with the 800 HP Wright R-1300. Installed diameter is 10 foot 0.5 inch. P-51 air racers and Tsunami, loved these high-activity factor blades The prop manual and revision update is attached.