A small clasp on the patented cap locking device clips onto the rim of the tube. Autoclavable when open (121°C; 20min.). Can be opened and closed easily with one hand. With frosted labelling area. The clasp on the cap prevents the lid springing open accidentally (e.g. when heating). Excellent mechanical stability for centrifugation. Graduated. Safe-lock reaction vessels are also available in Eppendorf Biopur® Quality. 0.5ml and 1.5ml capacity Safe-lock reaction vessels can be centrifuged up to 30 000 x g.