Bio Plas 4030 Polypropylene 1.5mL G-Tube Snap Cap Microcentrifuge Tube, Autoclavable, Natural (Pack of 500) Microcentrifuge tube capacity: 1.5mL Flat top lid forms an extra-tight seal that will not come open during processing Inscribing patches: all flat top microcentrifuge tubes have a textured writing surface on top of the caps Easy to open with thumb pressure; fully autoclavable for sterile applications Needle access: needles can be inserted through the target in the exact center of the lid of the microcentrifuge tube