[Size] Thread size of NPT: 1/4-18 NPT; OD of barb: 3/8 inch. [Material] Made of aluminum alloy 6061-T5, anodized black surface. [Application] Widely used in oil cooler, fuel tank, air cooled motor, fuel system etc. [Seal] The NPT side is sealed with tapered threads,please use sealant or PTFE tape to ensure a better seal. [Installation] When installing barb fittings, it is recommended to use clamps to ensure sealing.