Usage Tips: Suffered from different sizes of funnel and flask caps? You need our adapters. Different size can be fit for different diameters. You can use a single one or nest adjacent sizes together to fulfill your task. Also it helps reduce the risks from insertion and removal of glass stems via these rubber cones. Features - Color: Green - Material: Rubber - Size: About8.30X8.30X3.30cm/3.26X3.26X1.30inch - It is made of rubber material, is flexible and can be used for a long term. - Easy to wash and use even from oil with warm water and add little soap. - Different diameters, suitable for different sizes of experimental apparatus. - Can reduce the risks associated with insertion and removal of glass stems through these rubber stoppers. - It has reasonable design, simple operation method, and saves time and effort. Packing list8 x Funnel Adapters