This 18″ high performance, standard rotation flex fan features 6 stainless steel blades and a black powder coated hub and is rated for engine speeds up to 8,000 rpm. Great for applications where space is at a premium. Dimensions: Diameter 18-1/4″, Flange bolt spacing 1-3/4′ – 2-1/4″, Depth 1-1/8″, Mounting surface to front 1/4″, Mounting surface to rear 7/8″, Blade pitch 50°.