OPTIMUM® BestSEAL™ Brand • Cap designed with optimally best seal for sample security • Audible “click” assures cap closure • Cap opens easily with audible pop. • CERTIFIED RNase-DNase-DNA-Pyrogen Free. • Low Retention option – for minimal sample retention • Will withstand up to 20,000 x g, in fully supported rotors. • Accurate graduations. Temperature Range: -80°C to +121°C. • Boiling or freezing of tubes will not pop caps open. • Packed in premium, self-standing DispenserPacks.