1.Capacity:250ml; Color: Clear; Material: 3.3 Borosilicate Glass; Size:250 X 80mm/9.84 X 3.15 inch (HOD); Flask Neck Outer Diameter:21mm / 0.83 inch; Flask Neck Inner Diameter:15mm / 0.59 inch; Flask Cap Diameter:14 mm / 0.55 inch; Tolerance:20 degrees celsius±0.15ml; Packing List:1Pcs X Volumetric Flask 2.Advantage: The volumetric flask and the stopper are made of low expansion coefficient thickened borosilicate glass which can resist high and low temperatures and has superior chemical durability; The bottle mouth has a glass stopper to reduce evaporation and prevent liquid leakage. The long neck shape is convenient for holding and shaking to mix liquid; The transparent bottle body and accurate white graduation line ensure the accuracy of your experiments. 3.Instruction: When pouring liquid, use a glass rod to slowly transfer the solution, when the liquid is close to the scale line, you can use a dropper to drip slowly until the liquid concave surface reaches the scale line, tighten the stopper of the bottle and shake moderately to mix the liquid evenly 4.Application: Suitable for various occasions, the flask is suitable for a variety of occasions, such as laboratories, chemical rooms, and so on.