Polyform F-11 Twin Eye Fender 21.2" x 57.5" - Black [F-11 BLACK]F 11 Twin Eye Fender 21. 2" x 57. 5" Black Polyform has been producing the F Series fender for over 50 years and there is no comparison when it comes to quality, range of sizes, and protection offered. The F Series fender has offered protection to the world's finest yachts and fishing vessels. Why? Because the owners and captains of these prestigious boats know that they can rely on Polyforms F Series fenders to offer the size, strength, and