Extreme Max 3005.2178 Post Trailer Guide-Ons - 65" Post One pair of Guide-Ons; 60 steel support beams with slip-on PVC guards total 65 height Easy, bolt-on installation Zinc-coated for freshwater corrosion-resistance, not intended for use in saltwater or brackish water Fits bunk or roller-style trailer frames up to 3" wide x 4.25" tall* * Hardware to fit taller trailer frames (5.25", 6.25", 7.5" and 8.5") is available, see long description below