4.0 Dip Tube 3/4" 14 NGT Connection 375 PSIG Relief Setting Type 1 ACME and POL Typically compatible with sizes DT 3.9, DT 4.0, DT 4.1, and DT 4.2. This 20 lb. LP OPD valve has a 4.0 Dip Tube and fits most typical 20# propane tanks, most commonly used for barbequing. Type 1, standard. Please refer to the cylinder collar to confirm the correct size required for your tank. This is typically compatible with sizes DT 3.9, DT 4.0, DT 4.1, and DT 4.2. Features: GH-CA-RO Type 1 ACME and POL Relief Setting 375 PSIG Container Connection 3/4" 14 NGT 4.0" Dip Tube Compatible with 20# LP Must be installed by a qualified cylinder technician due to torque specifications. Compressed gas cylinders and valves are dangerous. Please use caution.