
I'm not stating this as a fact but being from Portland, Oregon I like to think that the Leatherman Tool was the first multi tool to hit the market with any success. Since 1983 and long before multi-tasking was a household term gadgets abound. As could be expected multi tools for bikes have shown up for cyclists as a new best friend in "keeping the donkey light" as we like to say when packing our gear.
"Hehe, last time I saw a bike tool kit it was the cheesy old crusty crap tools in a zippered vinyl case, held in place with elastic webbing. They weighed a ton and weren't very good!"

One of the reasons I prefer the Topeak Hexus II is it's very thought out design which in its' simplicity has managed to provide one of the best features missing on most all other multi tools. Namely the chain holder which looks like nothing more than a small piece of wire and if you didn't know it an actual tool to be removed and used you would think it was just part of the tool itself.
One of the two included tire levers has a built in hex bit for attaching the torx bit (included in the tool) and fits as a handle for the chain tool shown in photo above.
If you're looking for some much needed open or box wrenches either carry a Leatherman Tool, a small adjustable wrench or pliers or consider the Park MTB-3 Rescue Tool. Box wrenches are something to consider if you have fenders with fender stays, some rack stays and some older model derailleurs and bolt on wheels as for example many internally geared three speeds.

Although I had to replace the chain tool on my older MTB-3 it has been a reliable tool to keep in my pack and have helped others on several occasions with it. Other than most of the popular nut sizes covered by the box style wrenches the MTB-3 also provides a mini saw style knife blade and a cute little bottle opener molded into the chain tool handle. The tire levers do not include a spoke holder and are a bit wide if you have a stubborn tire that needs a smaller lever to get the bead started over the rim. Another factor some bike folks consider is it's bulk and weight compared to the Topeak or many other multi tools though comes with a nice carry pouch that can be worn on a belt. Of course this tool lacks the little wire thingy for holding two ends of the chain for repair like that supplied in the Topeak Hexus II.

Looking to add this to my kit on my mountain bike for touring and commuting.

This tool fit the needs of the three speed and I like the spoke wrenches notched on the box type wrenches. Although this tool is of a no name brand it has worked well when I needed it and is still a very solid quality item that I keep in the bike's saddle pack.
Very reasonably priced for the budget minded and makes an excellent gift like the other tools reviewed here.

Any of the multi tools discussed here can help get you out of a bind whether it's on the trail, commuting or on a long bike tour when it's essential to have some basic repair items.
this great guide on the best multi tools from Gear Hungry.