For easy labelling on frosted flat cap. The frosted flat cap. Separate caps decrease operating time. Thin walled tube for best heat transfer. Made of USP VI Polypropylene. Free of DNase, RNase, DNA, PCR Inhibitor, ATP, Endotoxin. All products are ready to use in PCR. Autoclavable. Evaporation rate below 5%. Small package can avoid contamination by different researchers. This items contain tubes and caps.