Abstract: A clamp adapted for mounting on a flexible tube to control flow therethrough, said clamp having a pair of parallel legs connected by a spring element whereby the legs may swing toward and away from each other, a flexible catch arm on one leg having a catch adapted to engage a latch on the other arm, cooperating cam means on the catch arm and latch to swing the catch arm away from the latch upon movement of the latch carrying leg toward the other leg whereby the catch is cleared by the latch which allows the catch arm to swing toward the latch and engage same to retain the legs in close position, this movement causing confronting clamping elements on the legs to compress the tubing therebetween to close off flow. Openings are provided in the catch arm and spring element to frictionally receive the flexible tube and retain the clamp on the tube thereby.