The Fast, Low Cracking Pressure - 5 Psi product is designed with a 1/4 Inch NPT Control Port for efficient performance. It offers (2) 3/8" Reservoir Ports and (2) 3/8" Delivery Ports, replacing the Midland KN28500. Additionally, it fits most makes and models. The VV-034057 variant features (1) 3/8" and (1) 1/2" Reservoir Ports, (2) 3/8" Delivery Ports, and replaces the Midland KN28510. Lastly, the VV-034058 model includes (2) 1/2" Reservoir Ports, (2) 1/2" Delivery Ports, and replaces the Midland KN28520. These products are sold individually and provide practical benefits for various applications.