Steampunk makers crafting supply. Very strong looking piece, perfect for any industrial design application. Impeller is 8" diameter, 1.75" thick, weight is around 2.5 pounds. Impeller was recycled from a retired State of Michigan web printing press (newspaper press) that supplied the State of Michigans House, Senate and Executive branch with copies of bills to be evaluated. This piece is of a heavy duty cast aluminum alloy and is in excellent condition. The impeller has minor wear but was only extracted from its housing for repurposing, it was not damaged or pulled for replacement. The pump that it came from was simply outdated for our printing purposes. Center hole measures 9/16" and the bolts measure a distance of 1.4375", center to center.