Pyrex Vista 250 ml Round Bottom Boiling Flask is made of borosilicate glass and features controlled wall thickness to offer balance between thermal expansion and mechanical strength for shock resistance. Flask has full length outer 24/40 Standard Taper joints with shorter necks. Shipping Details Shipping Type: parcel Free Shipping: true Specifications Maximum Age: 12 years Capacity: 250 mL UPC: 885634245658 Allergens: Contains No Allergens Grade Level: Middle-High School Specialty Shops: Clearance SUOM Description: Each Brand Name: Pyrex Description: Flask Round Bottom Boiling Material: Glass Graduations: Yes Material Type: Borosilicate Glass