Wheelchair users can power their ventilators, as well as phones and communications devices, via their wheelchair’s batteries by using the PowerTech Sigma. The unit includes two USB ports for easy charging of phones and tablets; a diagnostic LED light signals when the unit is ready to use. A two-wire installation of this 4.25″ long, 5.5″ wide and 1.75″ tall sealed unit makes it friendly for technicians as well.