SS-520 Cluster Rocket This is a sport-scale model of a Japanese sounding rocket. The SS-520 was a two-stage rocket, the kit is single stage. The real SS-520 rockets can reach altitudes of 800 km to conduct scientific experiments and gather data. This flying model rocket doesn't go quite as high. Good thing too, it would make recovery impossible. The SS-520 rocket does, however, fly on a cluster of two 18mm motors for added fun and excitement. The self-adhesive decal sheet includes fin wraps, lettering, and body wraps. The nose cone and antennae area (right below the nose cones) is painted. $26.95  Dimensions Overall length : 30.15" Diameter : 1.637" (BT60) Fin Span : 5.597" Weight : 3.7oz Recommended Motors Estes® 2 x B4-4, 2 x B6-4, 2 x C6-5 Challenges While the four small antennae and balsa fins are pre-cut, handling the small antennae offers a challenge. This makes the SS520 kit close to a skill level 3 kit, but not quite. Parts Parts include 1/8" balsa fin stock, fin template, two body tubes, coupler, laser-cut plywood centering rings, and other parts needed to build this model rocket. Supplies such as glue, sandpaper, and paint are not included.