The Atlas Sound EFT6-4 top-mounted fan panel provides quiet and effective dissipation of heat, for equipment mounted in Atlas Sound racks or cabinets with a 6 RU or greater open top (100, 200, 500, 700, & FMA Series). For installation in racks with greater than 6 RU top opening, SPF2 Series filler panels are suggested. Unit works best for .625" recessed rail applications; however, may be used in surface mount applications where the additional 1" height is not an issue. In addition, this product may also be used as a front or rear mounted fan panel within any rack or cabinet.