The Camco FasTen XL Leveling Blocks allow you to stack the interlocking blocks to the desired height for safe and easy leveling. The new, larger size has an increased weight capacity of blocks individually and in a stack, and also provides more surface area for leveling. Each block adds a full inch to stack height. Camco’s FasTen XL Leveling Blocks can be used with single wheels, dual wheels, hydraulic jacks, tongue jacks, stabilizer jacks, 5th wheel jacks, and tandem axles. The convenient carrying handle secures blocks together for storage and easily pulls up for carrying, or pushes down for more compact storage. Individual block measures: 10.5” x 10.5” x 1.5”. Stack height should not exceed 4.5".