Unlike any ruler you've seen before, the glow ruler is designed to bring light where you need it – the lines of your ruler! Great for both light and dark fabrics, this ruler has been designed to make fussy cutting easier. The ruler lights up the fabric, helping you see details, and making for more accurate fussy cuts. The Glow Ruler has a battery that is charged with a USB-C cable. Simply press the power button on the panel to light up the lines on your ruler. The Glow Ruler can also be used when the light is off. The battery lasts 6-8 hours on a full charge