Dynomax 42310 Exhaust J-Bend Pipe Mandrel bends improve flow capacity over traditional bends Dynomax Performance Exhaust, a leading performance exhaust brand built on over 20 years of market leadership. Each and every Dynomax product is backed by engineers who what you want and expect out of a performance exhaust product. Combine state-of-the-art engineering with quality material to provide exceptional strength and durability Dynomax premium pre-bent pipe is manufactured with precision benders, and then fixture checked, insuring every part is a perfect fit, providing quick and easy installation. Pipe diameters are increased from OEM sizes to improve flow and increase power.