Add a payload section to an existing model, or use when designing your own models. Includes payload tube, screw eye, balsa nose cone and balsa transition section (or bulkhead). The first number in the code is the size body tube the shoulder will fit into. The second number is the size of the payload tube. The third number is the length of the payload tube. So, for example, the PS - 6070H - 9 payload section fits into a T - 60 tube, while the payload tube is made of T - 70H tube (or a similar diameter in the case of the clear or colored sections) and that tube is 9" long.