Ensure RV Stability: Eliminate most movement with the strongest RV stabilizer blocks available. The corner ridges keep the foot secure and stable. Unique design provides the most stability & strength. High Quality & Made in the USA: Patent-pending design by American engineers, these US-made heavy-duty jack blocks for travel trailer are made the old-fashioned way, UV-resistant and built to last. Perfect Fit: Suitable for 9" large round jack feet found on many 5th wheels & RVs. The shorter 4.25" height of the trailer blocks for jack makes them convenient for stabilizer jacks, compared to a bucket block. 10,000 lb-Capacity. The larger surface area of these camper jack blocks created by the web design on the bottom of the block is a more stable surface area than alternative blocks. Size: Made of UV-resistant recycled plastic, the recessed pad area of these camper blocks for jacks is 9.25" circle with a 5.25" gap between ridges. Each block is 10.5x10.5x4 and weighs 6.8 lbs. The OX BLOX MAXX Trailer Blocks are designed specifically to fit the 9" round RV drop legs found in most 5th wheel trailers. These rv blocks for stabilizers are made in the USA of 100% recycled plastic and are UV resistant, making them the kind of block that will last a lifetime. Each trailer jack stand block is 4" tall and is stackable so you can get 8" of height or more without losing any weight capacity. Each block weighs about 6.8 lbs. If you're searching for a block for your RV, camper, trailer, 5th wheel, toy hauler, or motor home, the OX BLOX MAXX is a great choice. The camper stabilizer blocks are professionally engineered and are as strong as an ox. They are made in the USA from recycled plastic and are UV and temperature resistant. They are made to last. This is the perfect block for camp trailers, 5th wheels, boat trailer, horse trailers, or anything else that needs support blocks. The jack blocks for rv camper is designed to fit pad jacks, post jacks, stabilizer jacks, wheel jacks, and more. You can even stack them on top of each other and use them to support the frame. It works well on virtually any surface including gravel, grass, dirt, and pavement. Unlike other blocks, the OX BLOX RV jack stand blocks will hold stable in a variety of circumstances.