Designed specifically for column selection, sample clean-up and enrichment, column programming, back-flushing and other stream switching operations. Six peripheral ports (no center port) are interconnected through a two-position rotor. Low volume flow passages (0.6 mm I.D.) minimize dead volume that can affect column switching analyzes. The pressure limit is factory set at 5000 psi (350 kg/cm2), but can be adjusted to 7000 psi (490 kg/cm2). The flat-face seal is easy to adjust.