The new Stealth-RO low pressure, cold water, high flow membrane (HL# 22122) is designed for people who have low water pressure and/or cold water. Low water pressure at the tap (45psi and lower) can decrease the flow of a reverse osmosis product water. Cold water temperatures also can dramatically decrease flow rates. Although we offer a booster pump for our Stealth reverse osmosis system, which can increase psi and overcome the negative effects of low pressure and low temperatures we now offer an alternative in the form of this special membrane. It is not recommended to run warm/hot water from your water heater into your reverse osmosis system so there is no practical way to increase water temperatures. With the help our new membrane one can achieve better flow rates than with a standard Stealth membrane (HL# 22120). The only drawback to the new membrane is it has a slightly lower ppm rejection percentage. This means that the ppm of the product water will be slightly higher with a low pressure, cold water, high flow membrane than with a standard Stealth membrane. The new membrane averages 93% rejection while the original Stealth-RO membranes has an average rejection of 98%. Another benefit of the new membrane is with standard pressures and temperatures (ie: 60 psi and 70 F water) you can expect your RO flow rates to almost double!!! For example if you are used to seeing 90 GPD from your standard Stealth-RO membrane you can expect close to 180 GPD for the new high flow membrane assuming your tap water conditions say the same. This revolutionary new membrane is a Hydro-Logic exclusive and will be a welcome addition to anyone with cold water and/or low pressures or anyone that wants to increase their flow rates.