Low-profile PS housing, PES membrane. An economical polyesthersulfone filter unit that is ideal for small-volume benchtop filtration. Wide, stable base design. Pore size and membrane type are imprinted in blue on the side of each unit. Sterile / graduated. Low-profile PS housing, PES membrane. An economical polyesthersulfone filter unit that is ideal for small-volume benchtop filtration. Wide, stable base design. Pore size and membrane type are imprinted in blue on the side of each unit. Sterile / graduated.