This is a dandy Gardner flyball governor, suitable for use with a large traction engine or stationary steam engine. The size is 2 1/4”. I'm told that the governor originally was attached to a large traction engine (make unknown) that for decades drove a sawmill in the bush near Temagami, Quebec. This is a pretty hefty governor, and its dimensions bear this out. The flyballs are 3 1/2” in diameter, and the pulley measures some 7” across. Bottom flange diameter is 7 inches outside, 2 1/4 inches inside (the hole). Holes, centre-to-centre across the diameter: 5 3/4 inches. Holes, centre-to-centre adjacent: 4 1/16 inches. Side flange has the same measurements as the bottom flange. Measurements are as close as I can get with a tape measure, but should give you the idea.... This thing is in really great shape for its age, it turns smoothly, the flyballs are free, the sawyer's lever moves and seems to work (can't really test it....), and there are no breaks, chips, or cracks that I can find. You can be the owner of a rare piece of mechanical perfection which will enhance the beauty and performance of your historic engine.