This model was, while it lasted, the home for my new Aerotech 18mm RMS motor; the mount was set up to allow use of a wire-tie to keep the latch from releasing the casing in flight, and thus avoid losing a $40 motor investment. Use of that casing was to allow me to fly the Aerotech C12 and D13 motors; the D13 will give D altitudes without the stress of a D21 expendable (and at much lower cost), while the C12 will give that "leap off the pad" performance without excessive apogee height. There is also a certified C6 reload for this casing, and a few uncertified reload kits (the B4 is one that's pretty commonly found). I don't expect to buy or fly anything uncertified; there is some debate whether it's even legal to do so, since those motors are legally considered fireworks in many United States jurisdictions.
Sadly, this model was lost after a single day's flying, totalling only three flights, on my very first flight using the Aertoech reloadable motor. I can't say for certain why, but the ejection completely failed to function, and the rocket lawn-darted from 1400 feet into a swampy region north of the flying field, taking my reload casing with it. My suspicion is that the ejection charge, which was retained by a huge-seeming red plastic cap, may have migrated to the front of its cavity under drag-force decelration after burnout, so that when the delay burned through, there was nothing there to light. Without recovery of the casing, there's no way to be sure.
After nearly an hour of slogging back and forth through the swamp, I finally concluded that it must have landed in shallow water and buried itself completely in the mud bottom -- there wasn't any sign at all of the rocket in about an acre of swamp that I searched. Fortunately, it was too early in the season for ticks and leeches.