A construction site is a dangerous place for delicate electronics. Milwaukee’s new M18 Power Source lets you charge cellphones, digital cameras, or mp3 players away from busy job-site outlets. The unit attaches to and is powered by an 18-volt battery (standard or compact) and has a USB port for plug-ins. It also works with Milwaukee’s M12 heated jacket, providing longer runtime than the 12-volt batteries typically used. ¦ Price: $29 (does not include battery). 800-729-3878. milwaukeetool.com.