Indicator for immediate visual indication of cooling water flow. Connects easily to water lines in any distillation set-up. Highly visible red ball rotates in circular channel as soon as flow begins. Ball’s rotation speed depends on velocity of flow. This permits easy regulation of water flow speed. Made of clear plastic. Size of indicator is 39 x 57 x 19 mm. Tube extensions take 1/4"" to 3/8"" I.D. tubing.