The 55-Plus monitor is a sterilized, ready-to-use disposable filtration unit that reduces laboratory workload and speeds sample processing. The monitor eliminates the need for washing and autoclaving filter holders and greatly reduces preparation and handling time. It has 50 percent more filtration area than conventional 47 mm filter holders and devices, resulting in faster flow rates. The 55-Plus monitor requires no filter assembly before testing, and can filter sample volumes up to 100 mL. These convenient monitors reduce routine testing analysis time. After sample filtration, liquid culture media is added and the base of the monitor converts into a Petri dish for incubation. There is no need for a membrane transfer step, enhancing ease of use and test confidence. The 55-Plus monitor base features a gridded microfiltration-type membrane bonded to an absorbent pad, which prevents the membrane from bowing when nutrient medium is introduced. A plastic adapter connects the 55-Plus monitor and a neoprene stopper. A graduated funnel fits onto the base and has a funnel lid, with a built-in magnifying "glass" to aid in the examination of discrete, pinpoint bacterial colonies.