These 3/8" X .370" NPT male pipe plugs are engineered with a Vibra-Seal coating, providing excellent resistance to leaks and vibrations. Designed for automotive engines, including L4, L6, V6, and V8 configurations, these plugs ensure a secure, airtight seal. Manufactured in the USA with premium zinc plated steel, the pack of 50 plugs offers both durability and easy installation with their hex head design. Ideal for high-vibration environments, these plugs are trusted by professionals for reliable engine maintenance. Enginequest has inventory in many different sizes of plugs. NPT, Metric and Japanese thread. Engine Quest produces high-quality OE-style replacement parts. Each part undergoes rigorous testing and inspections to meet EngineQuest's exact specifications. Designed for precision manufacturing and durability, our products ensure easy installation. With nearly 500 SKUs available, the company specializes in hard-to-find, in-demand parts, including those no longer available from the OEM, difficult to salvage, or with prohibitively high OEM costs.