In order to remain sleek and compact, most of today's cycling multitools lack a chain-repair tool. Well, the guys at Philadelphia-based Mineral Design have addressed that limitation, with their two-part Mini Bar and Barstow system. It consists of a pocketable magnetic multi-bit wrench, paired up with a separate chain tool that sits inside the handlebar.
The 112-gram (4-oz) Mini Bar is a welded steel T-wrench, that can accommodate 1/4-inch hex bits in each of its three ends. As is the case with the Replaceable Edition of Fix-It-Sticks, they're held in place by neodymium magnets. Those three bits, along with three others, are stored in a "bit rack" when not in use. Like the bits themselves, that rack is attached to the wrench by neodymium magnets, and is simply pulled off when needed.
Oh yes, and the Mini Bar also has a built-in bottle opener.
The 40-g (1.4-oz) Barstow Chain Tool is built into what is otherwise a traditional expanding handlebar plug, and comes with a 15-g (0.5-oz) matching non-tool plug to go in the other end of the bars. It reportedly doesn't rattle against the inside of the bars when the bike is in motion, and is removed and replaced using the Mini Bar to loosen and tighten its center retaining bolt.
It additionally has a receptacle at the inside end, for storing a replacement chain link.
Mineral Design is currently raising production funds for its system, on Kickstarter. A pledge of US$45 will get you the Mini Bar and Barstow, when and if they're ready to go. The system is demonstrated in the following video.