Engine starter rubber cap with metal starter cone and aluminum head for RC airplanes.Includes three rubber cap sizes: large (internal diameter 52mm, height 50mm, depth 25mm), medium (internal diameter 44mm, height 50mm, depth 25mm), and small (internal diameter 36mm, height 50mm, depth 25mm).Package includes 1 rubber insert, 1 aluminum head, 2 pieces of 6x8mm screws, and 1 hex wrench.