From the iconic American tractor manufacturer to the Austrian company renowned for creating women’s jewelry, some surprising companies have diversified into the defense market.

Here are four companies supporting U.S. troops and law enforcement with innovations that continue to show healthy, if not robust, defense-business expansion in an era of fiscal austerity.

Deere & Co.

Deere ( DE ) manufactures the emblem of America’s heartland, the John Deere tractor. Blacksmith and inventor John Deere started with the humble beginnings of an idea to help farmers, a blacksmith shop and discarded steel saw back in 1837.

Last year, the company celebrated its 175th anniversary with R&D exceeding $1 billion for the first time in 2010.

Widely recognized as a global manufacturer of agriculture, turf and utility and construction and forestry equipment, Deere has also become a big player in defense.

As Deere says in its defense tagline, the “Road to victory isn’t always a road.”

For the military, Deere manufactures two different models of a manned utility vehicle, the M Gator models A1 and A2. The company also recently introduced a popular special unmanned remote controlled utility vehicle called the R-Gator A3 Assisted Carriage System (ACS).

This robotic load carrier was developed with Boeing UK and unveiled at one of the world’s largest defense shows DSEi in 2011.

The R-Gator ACS provides support to dismounted personnel by reducing the weight they have to carry. The highly capable cross-country mobility platform is designed to keep up with them over rough terrain.

Soldiers often have to carry more than half their body weight in armor, equipment and supplies. This defense system is based on the popular M-Gator platform and means infantry can offload up to 63kg of individual equipment.

With a top speed of 32mph, the company says it is the fastest commercial off-the-shelf diesel utility vehicle on the market. To support special operations, Deere has also recently introduced the All-New Gator RSX 850i.

Swarovski Group

For more than a century, the Swarovski name has been synonymous with high-caliber crystal, precision grinding and polished jewelry stones and crystal products. The Swarovski family-owned company dates back to Austria 1895 when Daniel Swarovski invented the world’s first electric grinding machine and founded the business.

While the average consumer may associate the brand with jewelry, the company branched into defense more than 60 years ago with the introduction of their first rifle-scope.

Swarovski continues to supply the defense consumer with high-quality optics in an ever-expanding product list.

In the defense space, subsidiary Swarovski Optik is known for its binoculars, telescopes, rifle-scopes, optronic instruments, range finders and image intensifier tubes.

In 1994, Swarovski Optik introduced their first telescope and five years later the Swarovski Optik EL binocular won Field and Stream magazine’s Best of the Best Award for the decade.

Last year, the company introduced a range of new products from a New Custom Ballistic Turret, new Z6i 2nd Generation Riflescopes and new 32 mm EL binoculars with SWAROVISION technology through to new ATX / STX Spotting Scopes.

In 2013, Swarovski Optik North America has already introduced a new wind-compensating reticle to the Z6(i) rifle scope line. It allows the shooter to dial in the correct elevation needed for a shot and then compensate for wind utilizing the vertical marks along the reticle crosshair.

Swarovski Optik has so successfully expanded into defense it now has a market presence on five continents with products available in over 30 countries through sales partners.

Polartec

Polartec is familiar to civilians as an essential component to outdoor recreational apparel; however, in the defense space the company is recognized for responding to the needs of American military boots on the ground.

When the company became aware U.S. Special Forces operators were purchasing commercially available Polartec products with their own funds 15 years ago, Polartec set up a defense group applying the company's R+D resources to creating military specific products designed for the particular needs of a warfighter.

Initially, Polartec served the special operating force customer but quickly developed the business selling to the Marine Corps, Navy, Army and Air Force. The company now sells to all service branches, the Coast Guard and government agencies.

Polartec still keeps its first client in mind and just introduced Alpha, another new product for the special operator. Alpha is a new breathable insulation that allows the wearer to need fewer garments to accommodate a wide range of environmental conditions.

The company is also currently working on additional performance materials for each service branch, with a focus on flame resistance, ballistic properties, responsive textiles and signature management.

Polartec division manager David Costello said “government business has experienced significant growth over the past 15 years and is a important component of the company's overall business.  The government business is helping drive innovation for the company. We conduct funded R&D work on behalf of the Department of Defense and are uniquely qualified to create the next class of performance materials that provide U.S. forces with a distinct combat advantage.”

The American company has also succeeded in developing a market beyond U.S. borders. Polartec now sells to a wide-range of foreign militaries, for example providing the Republic of Latvia with its Field Uniform.

BOSE

Bose Corp. built its reputation creating high-performing audio products for the retail market, but the company is well known in the military space for its outstanding headsets specifically designed for combat vehicle crews and aircraft pilots.

Bose was founded in 1964 by MIT electrical engineering professor Dr. Amar G. Bose developing products for the civilian market. These days the company contributes tech to the full aerospace and defense spectrum, from NASA space shuttles and military air power through to operators on the ground.

Exposure to high levels of noise over time can induce fatigue, lead to temporary and permanent hearing loss, and adversely impact situational awareness.

To support military personnel who operate with extremely high noise levels in armored vehicles, Bose became the first company twenty years ago to supply the US Army with an active noise reduction system.

The Bose T5 Tactical Headset is designed to be rugged, comfortable and provide full-spectrum noise reduction. Intended for armored vehicle crews, it was designed especially with US tracked armored vehicles in mind like the M-1 Abrams tank and the Bradley Fighting Vehicle.

The Bose Combat Vehicle Crewman Headset is the company’s second-generation active noise reduction communications solution. US Army research confirmed that compared to the conventional DH-132 helmet, Bose’s design improved speech intelligibility scores to 89 percent while providing improved hearing protection.

Bose has also introduced a T5 Tactical Headset designed specifically for use in wheeled armored vehicles like the M-1114 "up armored" HMMWV "Humvee" and Stryker.

The first to introduce active noise reducing headsets to aviation more than two decades ago, Bose has also been a pioneer and key partner for US military aviation.

For the military aviator, Bose has recently introduced their latest innovation, an A20 Aviation Headset that features a Bluetooth communications interface, an auxiliary audio input and priority switching.

Allison Barrie is an English law qualified lawyer who has practiced for two international law firms. Her deal experience includes oil & gas, large-scale cross border M&A, corporate finance and banking. Upon moving into defense, Allison has looked at risk and resilience issues, emergency preparedness and threat forecasting for Fortune 500 companies.