Spectrum is a color-blindness simulator for the Chrome web browser. Installing it allows you to see what your website looks like for people experience a number of different kinds of color blindness including deuteranopia, achromatomaly, achromatopsia, protanopia, tritanomaly and tritanopia. It also includes a low-contrast option.

It’s a helpful tool for understanding how people who with red/green color blindness might experience your website, and is particularly useful for websites that rely heavily on red/green color variants to convey important information.