† The term "leak-proof" applies to Thermo Scientific Nalgene products that meet the following criteria: a) For cap sizes less than 100 mm For bottle/flask/funnel sealing systems, when filled with water, the water inside will not escape when inverted for two minutes under a gas pressure of 2 psig; b) For bottle/funnel/flask sealing systems with cap sizes greater than 100 mm , when filled with water, turn it upside down for 15 minutes, and the water inside will not overflow. Note: If other liquids are used for the above test, different results may be obtained. To ensure safe use, customers are advised to test Thermo Scientific Nalgene bottles and closures under planned application conditions. Thermo Scientific Nalgene products are leak-proof when used with Nalgene sealing caps at room temperature and pressure.