0.5 to 250 ml per minute, pump only, designed with one hole of each size to accommodate the following tubing, 1/4 in. Id by 1/16 in. Wall, 3/16 in. Id by 1/16 in. Wall, 1/8 in. Idby 1/16 in. Wall, 1/16 in. Id by 1/16 in. Wall and 1/32 in. Id by 1/16in. Wall