Flex sections like this are designed to allow for engine movement and vibration. If you build your entire exhaust or intake out of solid pipe with nothing to flex, something will probably break. Most people use flex sections like these in exhaust systems, but if you're building a solid intake with no silicone couplers, you'll need one in your intake too.
These are just the right size to work with our V-band rings. You can weld the stainless steel V-band rings to them to combine with aluminum components, or you can weld directly to your stainless steel pipes.
All flex sections are not the same. Many of the less expensive ones will not have a stainless steel braid on the inside, creating significant turbulence in the exhaust gasses and reducing horsepower. We've also noticed that many of them are listed as "stainless steel", but come with aluminized steel pipes which rust and leak significantly faster, wrapped in stainless steel braids. Our stainless steel exhaust/intake flex sections are some of the best you can buy, with stainless steel braids on the inside and 100% stainless steel construction.