I'm got tired of yeast-based CO2 injection because of fluctuating concentrations and constant need for maintenance, so I decided to look into pressurized. It seems that the most expensive bit is the regulator - some cost well over $100. However, I found this one for pretty cheap and can't shake the feeling that I'm missing some flaw - how can they charge so little for a dual-gauge regulator, solenoid, needle valve, and bubble counter? These parts together could cost up to $200 but this particular part costs ~$80 in various stores... what gives?