These screw cap tubes are expertly designed for the safe preparation, centrifugation, and storage of samples. Manufactured from high-purity, medical-grade polypropylene, they are suitable for a vast range of temperatures, from cryogenic storage to autoclaving. The defining feature is the leak-proof screw cap, which is fitted with an EPDM O-ring to ensure maximum sealability, preventing both evaporation and leakage. Available in conical or self-standing designs, and with knurled options that lock into special racks for convenient single-handed operation, these tubes are a versatile and reliable choice for any laboratory. Key Features & Benefits Leak-Proof Seal: The cap features an EPDM 'O' ring that ensures maximum sealability, preventing evaporation and leakage. Wide Temperature Range: The tubes are fully autoclavable and have an operating temperature range from -196°C to +121°C, making them suitable for cryogenic storage. High Centrifugal Strength: These robust tubes are designed to withstand a Relative Centrifugal Force (RCF) of up to 20,000xg. High-Purity Material: Manufactured using high-purity virgin USP Class VI medical grade Polypropylene (PP) that conforms to US FDA 21 CFR. Single-Handed Operation: Knurled tubes are designed to lock into compatible racks, allowing for convenient single-handed opening and closing. Certified Pure: The tubes are certified sterile (SAL 10⁻⁶), IVDR certified, and free from heavy metals, human DNA, ATP, and PCR inhibitors.