These are a Kellogg American style 321 pump. They deliver between 5 and 8 CFM (actual) depending on how fast you run them within the spec. They work perfectly fine, they just lack the oil ring that a Genuine Kellogg pump is known for. 2 Cylinder, I Configuration. Operating RPM : 400-800 RPM. 13.75 Flywheel Flywheel INLCUDED with package! 9 from the left mounting holes to the right mounting holes. 6.25 from the front mounting holes to the back mounting holes. The item “Replacement Kellogg-American Style 321 2 HP Air Compressor Pump” is in sale since Thursday, April 06, 2017. This item is in the category “Home & Garden\Tools\Air Compressors”. The seller is “airriteproducts” and is located in Houston, Texas. This item can be shipped to United States.