The BPFN18 is used together with the Sharp BP-FN18 50-sheet Staple Inner Finisher, which in turn is installed in several models in the Sharp BP series (A3 MFPs).
Compatible machines are:
Sharp BP-50C26 / BP-50C31 / BP-50C36 / BP-50C45 / BP-50C55Sharp BP-60C26 / BP-60C31 / BP-60C36 / BP-60C45 / BP-60C55(assuming that the machine is equipped with the B