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 and IP 55, NEMA type 12UR and UL approvalUV resistance (IP 55 version, RAL 7035)cut-out compatible to installation size 4 of the 3rd and 4th Generationalso available in black and in 24 piece packaging for faster assembly