Hydrogen H2 - LMH & LMHPLUS Series The LMH & LMHPLUS series use an electrolytic cell with a polymeric membrane (PEM) to produce pure hydrogen gas. The innovative gas-drying system of the LMHPLUS series is completely ordinary maintenance-free and can run operations 24 hours a day. The exclusive electronically controlled gas/liquid separator automatically checks for internal leaks when the unit starts. Furthermore, the constant control of the operating parameters guarantees maximum safety and the LCD touchscreen interface provides a simple and user-friendly management of all of functions of the unit. Stackability minimizes the use of valuable laboratory floor or bench space.