In accordance with ASTM E-542 and E-288 standards, it has been calibrated to Class A tolerances. Each bottle is individually serialized and comes with a certificate of identification and capacity that can be traced to NIST standards. The graduation line is clear and durable, and the inscription is legible thanks to huge white capital letters. A normal tapered stop is included. Low actinic stained glass protects objects sensitive to light. The protective tint of the bottle is an intrinsic element of the bottle, which maintains the mechanical resistance, chemical stability and temperature resistance of PYREX brand laboratory equipment. In an ISO/IEC 17025 recognized laboratory, the product has been tested and calibrated.