These gap seals give you an incredible improvement on elevator and rudder authority as well as reduce drag. Its a must have for all STOL aircraft. Made of EPDM closed cell rubber, they will hold up to harsh conditions and you will notice a huge difference immediately after install. All you have to do is press them in and go. No more ugly tape that gets dirt trapped in it and comes loose. In this kit there is enough material to do both elevator gap seals as well as the rudder gap seal (if needed).