PS housing, CN membrane. Feature a leakproof 1 ½ turn threaded screw closure. Green collar. Certified, sterile, graduated. Volume 1000 ml: 500 ml upper with 1000 ml receiver. The 1000 ml size is recommended for filtering aqueous solutions such as buffers. Depending on the particle load, throughput may not equal 1000 ml. PS housing, CN membrane. Feature a leakproof 1 ½ turn threaded screw closure. Green collar. Certified, sterile, graduated. Volume 1000 ml: 500 ml upper with 1000 ml receiver. The 1000 ml size is recommended for filtering aqueous solutions such as buffers. Depending on the particle load, throughput may not equal 1000 ml.