Resistant to almost all chemicals. Ideal for boiling organic liquids. Ultra-pure, virgin PTFE chips promote gentle, efficient boiling and help to prevent superheating, even of highly volatile liquids. Ideal for continuous extraction methods, such as EPA SW846 and EPA Method 1664 for oil and grease. Stones minimize "bumping" during reflux and distillation. Not affected by boiling acids, hydrocarbons, ketones, esters, alcohols or alkalies. Easily cleaned and noncontaminating. Shows no trace of face acidity or alkalinity. Will not scratch or abrade glassware and leaves no powdery residue. Usable up to 550°F (288°C).