“Henry. Improves the air in rooms greatly and makes a big contribution to increased energy levels and better sleep. The first few days the devices made an intermittent high-pitch noise (we order three ion boxes) but after they had been running for a few days the high pitch noise completely ceased in all three devices.
Highly recommend it, though not suitable to keep on all night as the fan noise is a little too loud. I have just ordered the battery-operated non-fan ion boxes hoping they might be suitable for overnight use. Overall a great little device that is very price competitive compared to other negative ion generators on the market and certainly delivers what it promises.”