Fisherbrand Microcentrifuge Tubes 1.5mL - 1.7mL Polypropylene Graduated Tube with locking lid Natural Fisher Scientific Description: Convenient, pierceable locking lids snap into place with one-handed operation Polypropylene tubes with flat tops Ideal for sample-handling applications, including centrifugation, boiling and freezing of specimens, incubation and storage With graduation marks for volume estimation RNase and DNase free Centrifuges that develop excessive heat may damage this tube.