Keep in mind guys that you can build your own Knobster for about $32.00 - For the price of one Knobster you can have 3-4 Dual Rotary Encoders and it will also work with Air manager 
Keep in mind guys that you can build your own Knobster for about $32.00 - For the price of one Knobster you can have 3-4 Dual Rotary Encoders and it will also work with Air manager