Curt 16310 X5 Fifth Adapter for B&W Gooseneck Hitches (Industry-Standard 5th Wheel Rails, 20,000 lbs. GTW) Converts B&W gooseneck hitches to 5th wheel base rails Square shank for use with square ball hole (shank hole is 2.25" from plate surface, not compatible with shallow-hole gooseneck hitches) Rated for up to 20,000 lbs. GTW (limited to lowest-rated towing component) Industry-standard base rails accept 5th wheel hitches and rollers Protected by a highly durable carbide powder coat finish and co-cured in a rust-resistant liquid Bonderite coating - Made in USA