The famous use-it-forever Connex Link. No tools needed to install or remove! Makes cleaning and drive train maintenance a breeze, and since they work with most chains on the market, you can bring a spare and be assured you can get you or your buddy's bike rolling in the event of an broken chain.
The Connex Link can be used to install or remove your chain without tools. Here's a short video showing how simple, fast, and easy, the Connex Link is: