Fisherbrand Centrifuge Tube 0.5 ml O-Ring Screw Cap Case of 2500 Tubes

The Fisher Scientific (Fisherbrand) 0.5 mL Screw Cap Microtube (often associated with Model 2681370 or similar series) is a robust storage vessel designed for applications requiring a more secure seal than standard snap-cap tubes can provide. Unlike the "pop-top" variety, this tube utilizes a threaded cap integrated with a silicone or ethylene propylene O-ring. When tightened, this O-ring compresses against the tube rim to form a hermetic, leak-proof seal. This barrier is critical for preventing sample evaporation during long-term storage and protects against leakage when processing hazardous or radioactive isotopes.

The tube is manufactured from high-quality polypropylene (PP), which provides excellent clarity for viewing sample volume and high chemical resistance. While the exterior is often skirted (meaning it has a standing rim that allows the tube to stand upright on the benchtop without a rack), the interior maintains a conical bottom. This internal V-shape is essential for maximizing sample recovery, allowing you to aspirate the very last microliter of liquid—a crucial feature when working with the small 0.5 mL volumes typical of PCR or enzyme storage.

Because of the robust screw-cap design, these tubes are capable of withstanding extreme conditions that would pop a standard cap open, such as boiling water baths or deep freezing in liquid nitrogen vapor phase. They are typically rated for high centrifugal forces (often up to 20,000 x g) and are autoclavable, allowing for sterile reuse if needed.