Beaker cover fits 250ml PTFE beaker. Isostatically molded beaker cover (watch glass) from virgin PTFE is machine finished to give a smooth surface for ease of cleaning and to eliminate contamination. Virtually immune to chemical attack, only attacked by some fluorine containing compounds at high temperature and molten alkalis metals. Working temperature range is from cryogenic to 260°C. Diameter: 80mm. Per each. Dynalon® #: 315384.