Understanding Class A vs Class B Glassware: What's the Difference?
If you've ever picked up two identical-looking flasks and wondered why one costs almost double the other, you're not alone. The answer usually comes down to one small stamp on the glass: "Class A" or "Class B." This tiny label decides how accurate your measurements are — and in a lab, accuracy is everything. This guide breaks down what Class A and Class B laboratory glassware actually means, how the two differ, and which one you should be reaching for on your bench. What Is Class A and Class B Glassware? Class A glassware is manufactured to tighter tolerance limits, meaning it measures volume more precisely. Class B glassware has looser tolerances — usually about twice as wide as Class A — so it's less precise but more affordable. Both are made from the same basic materials and look nearly identical at first glance. The real difference lies in how carefully each piece is calibrated during manufacturing. Standards bodies like ASTM International and ISO...