Which tool is primarily used for large-scale construction and yields little or no torque reaction?

The correct choice, the pulse tool, is designed specifically for applications where it is essential to minimize torque reaction. This characteristic makes pulse tools ideal for use in large-scale construction settings. They operate by delivering short bursts or pulses of torque rather than a continuous flow of energy, significantly reducing the backlash or reaction felt by the user. This design allows for more controlled fastening and less physical strain on the operator, which is particularly beneficial in environments where heavy machinery and tools are in use.

In contrast, while continuous-drive tools, pneumatic tools, and impact wrenches may all be used for various construction applications, they do not primarily focus on minimizing torque reaction in the same way that pulse tools do. Continuous-drive tools may lead to greater torque reaction due to their design, and pneumatic tools can produce significant force that can transfer back to the operator. Impact wrenches, although effective at delivering high torque, also exhibit notable torque reaction, making them less suitable for tasks where minimizing that effect is a priority.

Thus, the design and functionality of pulse tools uniquely position them for large-scale construction tasks that require reduced torque reaction.