Cool Tool essential oil extractor tube is the most productive filter tube ever made! High quality, laboratory grade, german Schott Pyrex glass provides safe and reliable equipment for extraction. High density polypropylene caps with gasket seals on both ends to secure the included replaceable stainless steel filter disks. Access openings in caps for easy solvent introduction. Product Features: 2" x 34" German Schott Glass Polypropylene screw on caps seal at both ends Easy access to fill and clean Compatible with strong solvents Strong and durable screw threads 3 Replaceable stainless steel filter discs Made in U.S.A. Patent Pending