Parts that hold the object are movable in angle and can be clamped regardless of thickness. Although the object can be clamped without lubricating with lumber etc. (If it is a soft counterpart material, it will be dented) In a metal slide a little. I think that using a material with high friction coefficient such as rubber type is better. To some degree of clenching power is required for clamping (too hard for women?), Clamping force priority, maintaining compactness, I think that it is good hardness. On the other hand, it can not be said that it is reasonable and strong.