Standard 30% efficient (green) filter. Best for general wood dust applications, or as the first (front) stage when using higher efficiency filters. It is the easiest to clean and the longest lasting. Superb in pairs! Better performance and longer life can be achieved by "stacking" two ZF20's (#ZH1002 filter frame required).
About Razaire™ filters. There are 4 different filters available for the Razaire™ Z530. While they work fine as single stage filters, they are best used in pairs (stacked). Adding an extra filter stage increases both the performance and the life of the filter, with little to no discernible drop in suction.
All filters are approximately 9.75" x 10.5" x 2".