The clamp is wide, four inches and holds round tubing well, without needing to clamp very tightly. I've read that clamping thin tubing can damage it, and to clamp the seat-post, when possible, The clamp is long and holds the bicycle away from the stand a bit further. The 100-5D clamp can be purchased for aero-tubing, and fits the Universal Top Tube Assembly. The stand is heavier than a portable, and doesn't fold up completely, but it has been the best first choice for me. There are several types of repair stands, and some frames probably shouldn't be clamped at all.