These clamps are solid metal with a small white plastic tip one either side of the clamp. The plastic is not smooth and leaves four mini bumps in your skin- similar to the pattern of "four" on a dice. These clamps leave their "mark" even when left on briefly. I clamped one on the fleshy part of my hand for a count of five, and these little dots are still present after three minutes. The two clamps are connected by a chain approximately a foot long. The chain is solid and well made. It is thick enough that it does not appear that it will either break or bend easily. (It's just about the right thickness to get caught in the holes of a picnic table!)
These clamps are the easiest clamps I've ever used. Squeeze and they open wide! You can then insert just about any body part and they fit. They are quite flexible and strong. They are not adjustable in tension though and the pressure may be too much for some people or some body parts!
As a metal product, they are easy to keep clean and store. The clamps don't collect lint or dust. I didn't experiment with lubricant or oil with these so I don't know about extensive cleaning. The specific type of metal was not provided so use some caution as water will cause most metals to rust.
Although I found these clamps very strong, the packaging is somewhat misleading. The following words are on the package insert. "Symmetry and agony. Don't let their elegance fool you. Butterfly clamps are not for the faint of heart. The main trick of this deviously designed invention? Pulling on the chain actually makes the clamps tighter."
I really tried to see if I could make this happen! The reality is that this clamps "tighten" so much in the first place that when you pull on the chain, you really do nothing until you pull the clamp off. (That can be its own unique torture!) I closely examined the device to see if there is any way this actually works in reality. Maybe, maybe - about a millimeter.
It's true they aren't for the faint of heart. They are strong, but don't expect extra strength with a tug.