GlowShift’s Notched Wideband Bung is designed for better fitment on the rounded surface of your exhaust system when you’re installing this adapter. The curved edge provides an excellent fit so that it will sit flush making the welding process easier. While this wideband bung adapter is designed for 2.5” diameter tubing, it will easily work with other diameters as well. The overall result is a seamless and more effective installation of your O2 sensor. Made from high-quality 304 stainless steel, the notched O2 sensor weld bung adapter is 1/2” tall with a thread size of 18mm x 1.5mm which is standard with most O2 sensors. GlowShift includes unlimited tech support and a one-year limited warranty with each purchase.