A set of five Corning PYREX low form glass beakers (#1000-Series) with a 3 Piece Magnetic Stir Bar Set. 5 piece Beaker Set consists of one each of 50ml, 100ml, 250ml, 600ml, and 1000ml beakers. 3 piece Magnetic Stir Bar Set, PTEF, Pivot Ring, consists of one each 12x7mm, 25x7mm, and 35x9mm. The 3 stir bars included can accommodate all beaker sizes within this set as well as most other larger beaker sizes of all brands. Griffin Low Form Beakers are made of 3.3 borosilicate glass. Double Scale, Heavy-Duty, beaded rim and a spout designed to have excellent pouring characteristics., white marking spot, and uniform wall thickness throughout. 3.3 borosilicate is the highest level of inert glass available. Designed from ASTM Specification E960, Type I requirements. If you have any questions or concerns, please contact us. We are happy to make it right!