Stainless Steel 304 for corrosive environments, rigid and durable body design Precision CNC machined for tight, leak free performance and has polished finish appearance NPT 1/2" threaded, at least 7 threads count (ONE WAY THREAD!!!); thread starts at flange end Use for your custom oxygen sensor install, exhaust, down pipe, headers, exchangers and other installations where weld-in or weld-on metric connection is needed Easy to weld; Stepped double sided design with thick top head flange IMPORTANT NOTE: thread is tapered (one way thread) and starts from the flanged end and not the tail end (see drawing and pictures)! Stainless steel 304 weld-on bung for installations in corrosive environments. Threaded for standard tapered NPT 1/2". Fits through 1" hole. Easy weld with 0.2" top head border. Laser engraved on top face for easy identification. Let us know if you have any questions.