How accurate is the humidity control?

The specified accuracy is ≤ ±3% RH, with a display range of 0–99% RH. That figure describes the spread around the setpoint once the cabinet has stabilised, not the pull-down time. Real-world stability depends on how often the door is opened, the load inside, and the ambient conditions in the room. Cabinets used continuously with the door open are better served by the optional fast-purge configuration, which we can quote.