The phrase 'main instruments for' is correct and usable in written English.
It can be used to introduce a list of action items or activities that are used as tools for achieving a desired result. For example: "The main instruments for improving student performance are targeted and relevant teaching methods, a positive school culture, and effective parental engagement."
In the Jurm District in the center of the province, mullahs were the main instruments for pressing people to vote for Mr. Karzai, local residents said.
For 30 years, the main instruments for enforcing environmental conduct have been federal laws like the Clean Water Act, which direct the courts and federal agencies to impose penalties for noncompliance.
The main instruments for estimating the orientation of the magnetic sensors in space are the star cameras.
Guillier presents the results of rating Action Programs for Flood Prevention (PAPI), the main instruments for flood policy planning in France.
The package proved to be one of the main instruments for the fast and effective TRT diagnostics during debugging and operation periods.
Much has been learned in this regard through our experience with the AIDS epidemic, where spreading information, increasing protective factors and reducing risk factors have become the main instruments for addressing HIV prevention.
Nervousness could become alarm if the Northern Alliance becomes the main instrument for defeating the Taliban.
Should it be modernized to remain the main instrument for projecting military power for the United States and its allies?
And you know how they get those confessions: torture is the main instrument for solving a case.
The National Aeronautics and Space Administration selected Stanford University to develop and build the main instrument for the Gamma Ray Large Area Space Telescope, better known by the acronym Glast.
President Obama's budget for next year rightly asks for full financing of the $900 million Land and Water Conservation Fund, the government's main instrument for buying threatened open space.
