Choose between an advanced or performance series kit. 29mmt or 38mmt depending on field and ability. The 29mmt is an advanced series kit, which feature factory pre-slotted airframe and through-the-wall fin construction, the BBX is our sport scale version of the famous Black Brandt rocket. The 29mm motor mount is perfect for F and G motors and the rugged airframe can take I power if you can handle it. Parachute Recovery. The 38mmt version is great as a stand alone kit or ready to be married to the 3″ booster section.