Camco's Tandem Axle Trailer Wheel Chock is designed to secure your tandem-axle trailer against both forward and backward motion. Durable polymer construction with UV inhibitors. Wheel Chock can also be used as a tongue jack stand with a 400 lb. max tongue weight. Can be used with tires up to 26" in diameter with a minimum spacing of 7" between tires. Tire spacing can be affected by tire pressure and load so be sure to measure to be sure you have proper spacing.