This is a bellows style Goodyear air spring. The bellows air springs have one, two, or three convolutions in the flexible member. This double convoluted air bag is typically found on lift springs or axles for trucks and trailers, as an air ride spring, and also as an actuator or insulator on industrial and commercial applications. The specifications will vary on your 2B9-239, but double convoluted Goodyear bags are found in crimped design as well as sleeve type bellows. They will offer similar characteristics and functionality but the sleeve type has the end retainers permanently attached by pinching the flexmember between the end retainers and external crimp rings.