We needed to locate the columns for this structure. Our only access to a few of the column bases that were under this deck was through this hatch. We set up as low as we could with our instrument and standard tripod. The tripod feet have new points on them and we made substantial divots in the concrete where the feet needed to be. It was still very risky and I wouldn't have tried it but we only needed a few shots from here. After this I decided that I needed a better way to get low set ups. It doesn't happen very often but it would be nice to be prepared. So I took an extra tripod that I had and modified it so I would be able to get lower set ups when I needed. I disassembled the standard set, cut all the leg pieces in about half, drilled the clamp and stop holes and reassembled the tripod. It works exactly like the standard set and is very stable at low set ups.