This is a set of four sleepers, two of each: 30" and 36", old school type such as you'd see in the 50's to 70's. There are two different heights so as to fit most cab types. Should you have any issues, contact me via the direct shapeways link, or via email to modelmechanic@gmail.com . Be sure and 'follow' me as a designer to get the latest updates for new releases.