The PTFE separating funnels are isostatically molded from pure virgin PTFE resulting in a highly inert material, with very heavy wall construction, one that could stand up to nearly everything one might want to put into them. The super-smooth internal finish means that virtually nothing sticks to it. The bottom is precision machined for good transfer of material. The stopcock houses a PTFE encapsulated “O” ring seal for total leak-free performance. In addition, there are mini-hand grips also for ease of handling.