Omnipure L Series Single Plastic Bracket with Screws. The L-series combines the best technologies into an easy to use versatile package. A patented keyed head design insures each cartridge locks into place with 1/4 turn. Heads are available with Omnipure’s auto shut off valve system, making filter replacement a breeze. With a full array of media available, the L-series can address all your point-of-use filtration needs.