Above are some pictures of GHB's frames. The pictures show a 4x4, a "pie piece" and a full 4x8 frame. The 4x4 shows the side with velcro covering it. This helps to cushion the plywood surface and hold it in place. It's just a strip of "fuzzy" velcro and the plywood goes on top. You can also see the holes used to bolt the frames together. They are also in sizes 2x8, and 2x4. As GBH said., they are very light and easy to transport. We have full trailer width jockey boxes and they slide easily in and out. They really make a difference as far as ease and quickness. Last week, we built an 8x12 floor on a slope in about 15 minutes from laying them out to the dolly sitting on it and ready to go. I hope these pictures help!