OP18X18R Rubber Outrigger Pad 18x18x2 Inch - Heavy Duty Solid Crane Pad with Textured Surface & Built-In Handle - Perfect for Concrete, Pavement & Off-Road Use - Ideal for Construction, Crane Operations & Equipment Stabilization

These are made for heavy equipment like cranes and backhoes that weigh considerably more than my 5th wheel RV, so these are probably overkill, but I'm glad I bought them. Because they are so big and heavy, I only use them on my front stabilizer jacks. My trailer weighs 17,000 pounds. These support all of the weight that would normally be supported by the 5th wheel pin box when the trailer is connected to my truck (3000 or 4000 pounds). I like that they spread the load across a wide area on the ground when I am parked on softer gravel or dirt. Like I mentioned before, they are HEAVY. Something like 20 pounds each, so if you can't lift heavy objects, these may not be for you. I keep them in my truck bed, so that they are the first thing I pull off the truck when I drop the tailgate.My front jack pads are larger than the other 4 (10 or 12 inches diameter, I think) vs the other ones at the middle and back of the trailer that are 8 or 9 inches diameter. I use a smaller version made by a different company for those pads so there is less weight to support and the rubber pads also weigh less (10 pounds each vs the 20 pounds each of these pads). https://www.amazon.com/dp/B00HR7E1T0?psc=1&ref=ppx_yo2ov_dt_b_product_details I could probably get by with the smaller pads on the front too, but chose not to. All of these pads are pricey, but they do the job. You get what you pay for. I've gone cheap for too many times before and ended up buying something 2 or 3 times to "save money", then spent more in the long run.I use the square plastic blocks on top of these when I am on an unlevel site so the jacks don't need to extend as far. https://www.amazon.com/dp/B01N21JY71?psc=1&ref=ppx_yo2ov_dt_b_product_detailsPutting the plastic blocks on top of the rubber pads gives them a flat stable surface that won't bend as much so they are less likely to break from placing them on uneven or rocky ground. It's a system that has worked for me. Everything stacks neatly and I have gotten rid of the wood blocks that I previously used.