Premium quality fire cupping jar. Comes in six sizes. Glass density about 2mm. Made of highly resistant borosilicate glass 3.3. compliant to ISO 3538. Jar lip at the opening measures about 4mm in diameter. The information given below refers to the jar opening.
Special properties of borosilicate glass:
+ High temperature-change resistance
+ Low weight
+ Corrosion resistance
+ Neutral to aggressive chemicals
+ Resistant against acids and lyes
+ High UV transmission