Unicel FG-1248 Pentair Purex Replacement 25.38" x 10.75" 48 Sq Ft DE Filter Grid 48 Sq Ft Length: 25 3/8" Width: 10 3/4" Works for Purex/Pentair SMBW2000 Series /SMBW2048 Purex/Pentair SMBW4000 Series SMBW4048 Note: Collar has single notch and is covered with a black adapter. Length is measured from collar notch to opposite end of grid.