Models 3725-038 and 3725i-038(316 stainless steel) and 3725 and 3725i (biocompatible PEEK) are the most suitable manual valves to use with large sample volumes, high flow rates and preparative columns sized 1.0-10 cm (0.4-4.0”) in diameter. The ports accommodate 1/8” (3.2mm) OD tubing, and 1/16” (1.6 mm) OD tubing with the Adapter accessory (Part #6000-076). The 1.0 mm (0.040”) diameter passages allow flow rates of 10 to 100mL/minute with virtually no pressure drop.