A bubble counter is an important accessory in a CO2 system. Choosing a premium accessory is vitally important. INSTRUCTION: 1 Screw the bubble counter onto the needle valve. 2 Unscrew the top cap and fill 3/4 with water, firmly screw the top back on. 3 Unscrew the compression collar from the top of the bubble counter, feed tubing through the collar, and firmly tighten to hold the tubing in place. 4 Connect the solenoid valve, power cable and power adapter. Connect the outlet. 5 Use the regulator's needle valve to adjust the flow rate. 6 Count the number of bubbles going through the bubble counter and adjust the flow accordingly. 7 You can use a timer (Not included) to set the automatic switch. NOTE: Solenoid valve using pressure:0-7kg/cm². Need to use with a pressure reducing valve (CO2 Regulator)! Compatible with 4/6mm (3/16" inner diameter) CO2 tubing. PACKAGE INCLUDED: 1 x Bubble Counter with solenoid valve 1 x Power adapter 1 x Connection Cable 1 x screwdriver 1 x spanner