The BiOrb Air 60 Automatic Misting Unit is suitable for the BiOrb 60 2019+ models. The BiOrb Air Terrariums feature an integral microprocessor and humidity sensor which helps maintain vital humidity levels within the terrarium by automatically activating the ultrasonic mister as and when required. When the water in the top level water reservoir drops below the minimum water level, a sensor signals the microprocessor which activates the low water level indicator on the BiOrb Air. We would always recommend using the specially formulated BiOrb Humidimist as it contains electrolytes which allow the unit to detect and register the water levels easily and maintain correct function. This Automatic Misting Unit is easy to replace and slots simply into the top of the BiOrb Air Terrarium. Please Note: This Automatic Misting Unit will only fit the 2019+ models of BiOrb Air. To confirm which part you require please refer to your BiOrb Air instructions. This particular unit has a clear circle on the underside that shows a green circuit board which the older units do not have.