Why Filtered+

filter4d[intransitive] + adv.prep. (of people) to move slowly in a particular directionThe doors opened and people started filtering through. [intransitive] + adv.prep. (of information, news, etc.) to slowlyフェノールレッド liquid, 0.5%, sterile-filtered, BioReagent, suitable for cell culture; CAS Number: 143-74-8; Synonyms: Phenolsulfonphthalein solution at Sma-Aldrich