Made of top quality 3.3 borosilicate glass. Designed according to ISO 1042, DIN 12664 and calibrated to contain (TC, In). Each flask has a batch number printed on the flask. Batch certificate included (to be downloaded free of charge 
here)
reference: VFL3-5K0-001, capacity: 5000 ml, accuracy (ml): ± 1&comma:200, stopper: 34/35, pcs/pack: 1