These clamps are made of metal, with small rubber tips to cover the section of the clamp that contacts your nipple directly. The metal is smooth, pink and shiny, and the chain connecting the two clamps has a smooth drape. The rings that connect the clamps to the chain are well made and sturdy. Beneath the rubber tips, the clamps have metal teeth.
These clamps are adjustable. By turning the screws, you adjust how far each clamp closes. The farther the clamp closes, the more pressure you will feel. This allows you to start playing around with these clamps at a mild intensity, and increase the pressure if you would like a more intense sensation. The screw is easy to turn, and has a textured knob so it is easy to grip. If you desire a much more intense sensation, you could remove the rubber tips and use the clamps without them.
The length of the chain is ample enough to reach from nipple to nipple on anyone. These clamps would fit any size nipple. The tips of the clamps are wide enough for larger nipples, but would work for a smaller nipple as well.
These can be cleaned with a damp cloth as needed. Storage is simple: they can be thrown in a drawer or your toy box.
These clamps come in a basic clamshell package which takes up a lot more space than the clamps themselves, so it isn't ideal for storing them. There were no instructions, but they aren't really needed.
These clamps added a bit of fun to our experience. They can be placed and left on, or gently tugged for a more intense sensation. I wouldn't say they were painful, even without turning the screw to ease up the tension, but it will vary depending on your nipple sensitivity. I've been nursing for the last few years, so mine may not be at their most sensitive.