For easy labelling on frosted flat cap The frosted flat cap Attached caps help avoid cross-contamination between different tubes 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