The NIP NOS Great Planes O.S. Prop Adapter Kit is a must-have for any serious RC airplane enthusiast. This kit is compatible with O.S. .20-.40FP, .25-.46FX, and SF engines and comes with everything you need to attach the propeller to your engine. Made by Great Planes, a trusted name in the RC industry, you can be sure that this adapter kit is of the highest quality. This kit is designed for use with airplanes and is compatible with nitro and glow fuel. It is suitable for use with 1:4, 1:5, 1:6, and 1:8 scale models. The kit is made in China and is recommended for ages 17 and up. If you're looking to upgrade your RC airplane's propeller, the NIP NOS Great Planes O.S. Prop Adapter Kit is an excellent choice.