With Hlabs exclusive sealed/ported box design nomenclature it is easy to design your woofer enclosure to match your woofer parameters AND you can see how Thiel small signal parameters (VAS, QTS, and FS)affect your box design by viewing the various graphs. The beauty of this design kit is that you do NOT need a computer. The two sided design data is laminated with thick laminate. One side has the sealed box design data and the other side has the ported box design data. Included is an easy to follow single page instruction sheet and a seperate sheet listing speaker related terms and their explanation. This item ships in a mailer.