John, they ask whether it's going to be on concrete, dirt, or what. The installer had a pretty long masonry bit and drilled holes through the concrete (3 on each side), then he had what I think was 3' lengths of rebar with an ordinary hex nut welded on one end of each one and he drove those in. I'm thinking the holes he drilled in the concrete may have been just slightly smaller than the rebar (1/2" rebar, I think) because he drove them in with a sledge hammer and it took several licks on each one to get them all the way down. I didn't ask what they would have done on other surfaces. They also asked me whether electricity would be available (it was, of course), but I noticed on that special built trailer, they had a generator.