Estes 303158 Regular Engine Mount Kit Multi-Colored, Multi

You can build these mounts to fit BT-50, BT-55, BT-56, or BT-60 body tubes. There are parts included to construct a "quick-change" engine mount for flying lightweight "D" powered rockets with regular engines. This mount is designed so that it can be quickly interchanged between flights. There are extra parts, so save them for future use. Fully detailed assembly instructions with illustrations. INCLUDES: Two Engine Mount Tubes One Centering Ring Three Centering Ring Sheets Three Centering Rings (Thin) Two Engine Retainer Rings Two Engine Blocks Two Engine Hooks REQUIRES: Hobby Knife Sandpaper CA Glue, Wood Glue, or 5 Minute Epoxy Pencil Ruler. « less