The clear zinc finish on our 1,000 lb. Swivel Mount Trailer Jack is tested to a 100-hour corrosion resistance standard.The West Marine 1000 lb. Swivel Mount Marine Jack is designed for use with marine and utility trailers. West Marine tongue jacks are time-tested and application-proven. Retaining ring swivel mounts are made from heavy-gauge steel stampings that deliver minimal deflection and maximum support.Key Features Tested to withstand salt spray for 100 hoursAll mounts fit up to a 3" X 5" trailer frameBig 6" wheel diameter Includes all necessary mounting hardware 10" travel to 22" total extension Grease fitting makes maintenance simple One-year warranty