Rocker MF series magnetic filter holders are designed with double-layer magnets to ensure a tight seal between the funnel and support base. The user-friendly design can allow one-handed operation and prevent possible twisting and tearing of the membrane. One to more: Compatible with various kinds of bottle, vacuum flask with or without side arm to collect filtrate directly. Easy to use: Strong magnetic seal allows one-handed operation, prevents possible twisting and tearing of the membrane. Membrane guide on the base helps position membrane easily. Funnel Size: 9 cm x 17 cm. Filtration Area: 41 mm. Benefits: Versatile: Compatible with various kinds of bottles, vacuum flasks with or without side arm to collect filtrate directly. Easy to use: The strong magnetic seal allows one-handed operation and prevents possible twisting and tearing of the membrane. The membrane guide on the base helps position the membrane easily. Safety: PES (Polyether sulfone) construction, resistant to a wide range of chemicals and high temperatures, sturdy and unbreakable. Reusable: Withstands numerous autoclave cycles, saves money and energy consumption.