its the 2.1" sized rocket. 39" oal. Just looks and feels a tad stubby.So I can't figure out which kit is the PK-25. My Park Flier IRIS (the 1.63" kit) is at my other home(my house. At the GF's tonight, don't ask, it's complicated...), but I do remember that it has a second tube at least 8" long. If you can wait a day, I'll measure it tomorrow.