Mufan CO2 Regulator Dual Gauge w/ Bubble Counter (W21.8)  Part # 0532-84814476
 
CO2 Bottle attachment is W21.8 fitting / Interface
Accurate fine-tuning (regulate to 1 bubble/2-3 sec)
Fixed Fine Tunning Value
Material: aluminum alloy and acrylic
Dual gauge pressure indicators (tank volume and flow pressure / working pressure)
Includes - Single head bubble counter with internal check value
Approx size: Height 4.5" L x 3" W  4.51" H (with bubble counter attached)
 
Note - this does not include a solenoid / one can be purchased separately