HRV FILTER x 2 ( plastic fan box in roof)GENERATION 2 POST 2014 F8 ARIZONA 2 x HRV compatible Filters Product information High Efficiency Grade F8 EU7 Filter class EN779 Eurovent 4 4 Performance data based on ASHRAE 52. 2. 1992 Compatible with: HRV System ( Plastic box type) 300mm height 295mm width 95mm depth HRV compatible filter. Media is Lofted synthetic polypropylene with an extended deep pleated surface which allows for more media surface area, resulting in excellent dust loading