This set replaces the horizontal stabilizers and elevators of the base kit. While the Airfix parts are certainly nice in their own right, this set allows the control surfaces to be posed and have slightly thinner trailing edges for a more scale appearance. Be very careful trimming the resin away from the mounting tabs and test fit to ensure as close a fit as the kit parts provide. The elevators fit very well into a recess molded into the stabilizers. If you want to have the rear control surfaces offset this is the way to achieve that. Thanks to Aires for the sample of a well done set.