The chain can be worn in public, as a symbol of ownership that not many people would clue to. The weight serves as a constant reminder. With the rise of the hip-hop movement and the jewlery associated with it, there are few questions asked when seeing a woman wearing a heavy 'necklace'.

I prefer the curb style, an example at:
http://www.walmart.com/catalog/produ...A3895%3A109692
because of the style and weight It looks to be very similar to item #1634A (fourth down) on your first reference without the lock.

Depending upon the construction and care, a good chain will last years. I was given a chain necklace from my grandmother over twenty years ago and am still wearing it.

A chain is not designed for strain so as a form of restraint it would be inadequate.

For serious play you would require a proper collar.