same design as the PF series filterfanssnap fastener developed and patented by Pfannenbergdoor mounting without screws in accordance with VDE 0113 (EN 60204)simple filter mat exchange during operationwith integrated foam seal to enclosuredegrees of protection IP 54, NEMA type 12UR and UL approvalcut-out compatible to installation size 1 of the 3rd and 4th Generationalso available in black and in 45 piece packaging for faster assembly