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The bike weighs about 29 pounds. It folds up suitcase-small — to about 36 x 38 x 12 inches — and it was initially developed in 1997 for the military with seed money from a U.S. Defense Advanced Research Projects Agency (DARPA) grant.

It's called the Paratrooper, and the bike, as its name says, was made originally for parachuting soldiers. The procedure was: Jump out of the airplane with a bike attached on your back; deploy the chute; land, unfold your bike, and ride quickly off into the field.

Montague Corporation, based in Cambridge, Mass., sells its Paratrooper bikes to the U.S. military as well as common citizens. The folding design lets you pack the bike up small. In a few seconds, a rider can remove the front wheel, fold the frame in half, and pack it away. No tools required. 

The company () has photos of the bike in use for military missions in desert places that look like Iraq. But it has sold the Paratrooper bikes to any average

Joe for a couple years now at $879.

There are eight fold-up bikes in the current Montague line. They are popular with travelers who want to take a bike on an airplane or pack it into the trunk of a car. You can fold one up and stuff it under a desk at an office.

The Paratrooper model is a full-size mountain bike with 26-inch wheels and an aluminum frame. It has suspension and 24 speeds.

This winter, Montague will begin selling an upgrade, the Paratrooper Pro, which will come with a black color scheme and improved components and shocks. It will cost $1,049. Like the original Paratrooper — which only came in Army green — the Pro model is set up for use behind enemy lines, on tough singletrack trails, or simply for rough roads on your commute to work.

–Stephen Regenold is founder and editor of .