One embodiment is a unique replaceable filter element. The system includes a lock mechanism, a microcontroller, and an input device for receiving passing information. The method further includes shifting the absorbance spectrum to zero in a wavelength region. The base portion includes at least two lugs that extend radially from a position adjacent the annular portion towards the central portion, the lugs including at least two stepped segments. This method and apparatus are particularly useful for preparing polymers used in drag reducing agents for hydrocarbon transportation pipeline applications, as well as other polymers benefiting from narrow andor customized temperature profiles during production. The discontinuities in adjacent ones of the seal lines are disposed proximate opposite ends of the lines so that the discontinuities, the lines and the adjoining material form a tortuous channel providing communication between the interior of the bag and the exterior of the bag.