Which Briiv filters can I use in my unit?

The original Briiv unit can use the reindeer moss filter as its primary filter. 

The Briiv 2 and Briiv 2 Pro units can use the reindeer moss filter, or it can use the Yorkshire moss or activated carbon filter as the primary filter. These two filters cannot be used in the original Briiv unit. 

The original Briiv has a smaller fan than our newer model, meaning it isn't quite as powerful. The Yorkshire moss and activated carbon filters have a higher density than the reindeer moss filter, and using these with the original Briiv would make the unit inefficient and less effective at filtering your air.