The Andersen Trailer Jack Block takes the fuss out of stabilizing your trailer's jacks. Built-in magnets attach directly to the jack pad, holding the block in place - no sliding, no repositioning, no second-guessing. Designed for 5th wheel and RV trailer jacks, each block is rated to 8, 000 lbs., handling the load while reducing strain on your jacks during a stay. Stack two blocks when you need extra height when double-stacked, the pair supports up to 1, 500 lbs. The 12" diameter base sits firmly on the ground, and the 9-1/8" recessed pad on top keeps the jack centered and secure. Running a post jack? The 2-1/2" recessed post hole accepts post jacks directly, keeping the block from shifting underfoot. At 5.3 lbs., it stores easily in a bay or basement compartment until your next site.• Each block rated to 8, 000 lbs. (1, 500 lbs. when double-stacked)• 12" base diameter, 10" top diameter• 9-1/8" recessed pad centers the jack on top• 2-1/2" recessed post hole for post jacks• Weighs 5.3 lbs.• Made in the USA with a lifetime warranty Stacks up to 2 blocks when extra height is needed Fits post jacks through a 2-1/2"" recessed post hole Built in the USA & backed by a lifetime warranty | Andersen Hitches Trailer Jack Block with Magnets, Single 8 in Made in USA