This kit is meant to convert the Testors or Italeri B-66 kit into the Northrop X-21A Laminar Flow Control aircraft. Resin parts make up the top of the fuselage, wings, engines, laminar flow exhausts, and tail cone. The resin parts are solid, with a very slick surface finish and no visible airholes. There is a bit of flash along the mold seams and a couple of minor molding flaws on my parts. The engines have detail molded inside the intakes and have hollowed out exhaust cones (as do the suction compressors). The single page instruction sheet includes a drawing showing where to cut the B-66 fuselage for the resin parts. It also includes a three view drawing showing part layout and the paint/decal scheme. Text instructions are also included, along with a detail drawing for assembling the wings. It doesn't mention it in the instructions, but you'd probably want to drill some holes and add some supporting rods for the wings. A complete set of decals, including national insignia, finishes out the kit.