The saw is battery-powered, so make sure to charge it. The voltage amounts to 18 volts and would surely make a good addition to your toolbox.
From ManoMano
DCS391N 18V 165mm Circular Saw With 2 x 5.0Ah Batteries:18V - Dewalt
Tools4trade
Dewalt DCS391N 18V 165mm Circular Saw With 2 x 5Ah Batteries & Charger - 18V