<ul><li>Click the Scroll Lock light button to rainbow backlightThe mouse on the g21b kit is slightly smaller than the g21.The button-hanging protective cover is waterproof and dustproof.It is easy to carry and thoroughly cleaned to prolong working hours and bring a cool gaming experience.Type 104 keys easily in the darkBest for PC Gamers.Used in homes and offices.Give pleasant effect while using.</li></ul>