Quality metal and pretty clamps on the nipples.

After pressing clamps will be open and grasp the nipple.

Pressure force on the nipple depends on two factors. First - attracting force of the spring clips. Second, the pressure line to the terminals away from the the nipples. By pulling on the chain away from the the nipples clamps causing stronger force on nipple.

Therefore, they are playing with chain very interesting. When using weights to chain you can imagine what will happen ...

The chain is 30 cm long and can be disconnected from the terminals. Then, the clamps are separated, and their usage is more variable.