Adapts to your space with multiple color options. The colorful fabric doubles as a pre-filter, catching large particles and extending the life of the primary filter. Simply vacuum the fabric or toss it in the washing machine whenever it needs cleaning. Go without the pre-filter altogether for a clean Scandinavian look. Noise-levels are no louder than a whisper on the lowest speed (23 dB) and equivalent to the noise level of rainfall on the highest setting (56 dB). Unlike some air purifiers with strict rules for placement, the Blue 3610 uses a 360-degree air intake, meaning you can place it almost anywhere in the room without compromising performance. Energy efficiency (4-38 W) - certified room air purifiers are 40% more energy-efficient than standard models, so you can run your air purifier 24 hours a day without concern. Stay up to date on the status of your indoor air with the LED air quality indicator (AQI). The display changes color to indicate good, moderate, or poor based on the current concentration of fine particles (PM2.5) measured by the integrated particle sensor. Forget about adjusting settings and knobs - a single button controls it all and lets you know when it's time to replace the filter. After about 7 seconds, the button's LED light automatically dims to 0% brightness. The built-in LED warning system glows red when it's time for a change.