These PTFE filter reactors can be used for fluorine chemistry and with strong alkaline compounds that can etch glass. The head, head joints, body, stirrer-bearing, bottom filter assembly with valve, and stirring shaft with agitator are all PTFE. Even the O-Rings are PTFE encapsulated. The filter supports are polypropylene. The bottom filter assembly is either #50 or #80 Ace-Thred and threads in/out for easy capture of filtrate, or for cleaning. A Halar® coated stainless steel internal coil is included (in the 1 L size) for heating or cooling the contents. IKA RW 20 over head stirrer recommended.