Best way to put a chain together. Reusable--makes it easy to take the chain off for cleaning, etc. Have used for several years and have never had one come apart accidentally.
The price was right and it never hurts to have spare with you to get you home if your chain suffers a catastrophic failure. (I have never had one, but they say it happens, so....)
Works exactly as intended. Just put the two sides together, add some tension, and you've got a complete chain.