The Professional Products pumps are similar in physical size and appearance to Walbro or Airtex pumps with one very important difference. Our pumps have 1/4-NPT pipe threads on both the inlet and outlet port which allows users the flexibility of a wide range of fuel line connection fittings. If you want to connect to a 3/8" hose, use Professional Products fitting #10244. To connect to a -6AN hose end, use Professional Products adapter fitting #15242. See horsepower ratings below to select the proper pump for your particular installation. All three pumps operate at 45 PSI of fuel pressure. They come with an extruded aluminum mounting clamp which also acts as a heat sink. The aluminum mounting clamps are anodized in the colors shown below and provide a quick visual identification.