The Penguin Series A-A and Series A-B filter systems are all-purpose, compact, fully portable, corrosion-resistant, and metalless, and they require no floor space. If desired, both system types can be mounted outside the tank. Unlike one-piece submerged filter systems, Penguin A-A and A-B filter systems need not be removed from the tank for cleaning or cartridge change-out. The ACME threaded heads employed on single cartridge chambers can be easily removed by hand and a new replacement cartridge filter simply dropped in. All filter system models incorporate the unique Penguin design, which provides leakproof filtration with no liquid bypass.