Give your jacks a solid footing at the campsite. E-SDS RV jack block stands spread the load under your jack feet, cutting down on movement and sway in a parked trailer, fifth wheel, or motorhome. Each set includes two blocks molded from 100% recycled plastic that is UV resistant and tested up to 10, 000 lbs. A recessed 2.7" post hole helps keep post jacks from slipping, and corner ridges hold the jack foot steady. The top also accepts a 9" round fifth wheel jack foot. Each block stands 6.4" tall with a base of 11.1" L x 10.3" W. Stack the two blocks for about 12" of height when you need to reach more ground. Do not stack more than two. Features:• 100% recycled plastic, UV resistant• Tested up to 10, 000 lbs• Works with tongue, post, scissor, and pad jacks• Recessed 2.7" post hole and corner ridges keep the foot in place• Stackable to 12" tall, two blocks maximumPull them out of the storage bay when you set up camp and match your jack type and rig weight to the rating before use. Fits tongue, post, scissor, & pad jacks Recessed 2.7"" post hole helps prevent post jack slipping Stackable to 12"" tall, two blocks maximum | Camping World E-SDS RV Jack Block Stands for Tongue Jacks, 10000 lbs, 2 Pack