Fuser film sleeves designed for use with MF645CX, MF641, MF643, MF643CDW, LBP621, LBP623CDW, LBP621CW, 1025, M175, M176, M177, CP1025NW, M251, and 276 series printers.This replacement part is engineered to support consistent print performance and within compatible printer models.The sleeve aids in the fusing process by facilitating smooth paper passage through the heating unit during printing.