Bosch 14.4-volt impactor cordless impact driver.(Product/service evaluation)

I like to think that I keep up with building trends and new tools, so I was surprised to find a whole new category of power tools that I was completely unaware of: cordless impact drivers. While they look a little like conventional cordless drill/drivers, these tools aren't for drilling. They're designed solely for driving screws and tightening bolts.

Like their larger cousin, the impact wrench, impact drivers use a rapidly rotating hammer and anvil inside the gearbox. The force created by the spinning hammer striking the anvil explains how a relatively low-voltage impact driver can produce more torque than an 18-volt cordless drill. That force is also what gives impact drivers their distinctive rat-a-tat sound.

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