The Watson-Marlow 401/D1 auto/manual control ultra compact buffer recirculation pump is suited to those users wishing to maintain buffer recirculation during horizontal gel electrophoresis. The pump can be connected to the HU13, HU13W, HU13L, HU15, CHU20, HU20, CHU25, HU25, SVG-SYS, TVG-SYS, VG-SYS, VG-FAST96 and COMET units through buffer recirculation ports located within the lid of each unit.