Bests & Worsts Reviews from Amazon

This is a step up from the old versions with an air sensor and auto settings. The fabric off the prefilter is a lot thicker and is easier to put on and take off using velcro compared to the old 411. The old prefilter was a cylinder shape that was stretchy and very thin and seemed like it might tear easily if you weren't careful. These little guys are great for small rooms and with auto settings and a sensor you can just leave it in a guest room and it will turn on and off based on the particulates in that room so it doesn't waste effort on an already clean room. Even if you leave it on full time it uses barely any electricity costing maybe 3 or 4 usd a year. Compared to the previous two 411 models this has greater range, is cheaper, has auto settings, better prefilter, and has a sensor so there is no reason to buy the old ones.