Which tool is designed for smoothing surfaces?

The portable electric sander is specifically designed to smooth surfaces by using sandpaper or other abrasive materials powered by an electric motor. This tool can efficiently remove paint, varnish, or other finishes from wood and is capable of sanding various surfaces, including wood, metal, and plastic. Its ability to rapidly move and apply a consistent pressure makes it ideal for achieving a smooth finish on large areas or intricate details.

In contrast, the putty knife is primarily used for applying and smoothing fillers or putties rather than smoothing surfaces itself. The regular socket is a tool for turning fasteners, such as nuts and bolts, and does not serve any purpose in surface preparation or finishing. Pruning shears are designed for trimming plants and shrubs, focusing on cutting rather than finishing surfaces. Thus, the portable electric sander is the tool that distinctly fulfills the role of smoothing surfaces effectively.