These PCR tubes are made of high-quality virgin polypropylene and feature uniform thin walls for efficient heat transfer. Tubes and caps are compatible with most leading thermal cyclers, and are autoclavable. Caps, available as either flat or domed, fit perfectly and create a uniform, tight seal that prevents sample evaporation in the thermal cycler. Tubes are nonpyrogenic and RNase- and DNase-free. Certain models feature assorted packs of color-coded tubes for easy identification of samples.