I first learned about Pura from a friend whose house always smelled like a high-end boutique under every circumstance. Cooking project, water leak … no matter what was going on in her house at the time, I only ever smelled berries. Mercifully, the stand-alone, cylindrical Pura Plus has manual control buttons on the front. The smaller Pura 4 really is best for enclosed spaces, like a long entryway or a bedroom (note that both only work with 2.4-Ghz Wi-Fi). If you have high ceilings or any kind of open floor plan, you’ll get better results from the Pura Plus.