Rubber Cone Int. 20/14 – Ext. 26/19mm for Flask Neck 21 (Model 2162)

This high‑quality Rubber Cone Adapter is designed for use with Büchner Funnels, offering a practical alternative to boring large holes in traditional rubber bungs. The tapered design ensures a secure and airtight seal by fitting around the base of the funnel rather than its stem. This means the cone must be selected based on the flask neck size, not the funnel stem diameter.

Suitable for Flask Neck 21, this cone features internal dimensions of 20/14mm and external dimensions of 26/19mm. It is supplied individually and is ideal for creating a tight, reliable seal during filtration work in school and laboratory settings.

Key Features

• Designed for use with Büchner Funnels without modifying bungs
• Ensures sealing around the funnel base for secure fit
• Compatible with Flask Neck 21
• Internal size: 20/14mm
• External size: 26/19mm
• Provides an airtight connection during vacuum or gravity filtration
• Priced individually

Ideal for School Science Lessons & Laboratory Use

This rubber cone is a valuable accessory for KS3, GCSE, and A‑Level chemistry when teaching filtration techniques. It supports safe and effective use of Büchner funnels without requiring specialised or modified bungs. Perfect for:

• Vacuum filtration in organic and inorganic chemistry practicals
• Separation and purification experiments
• Demonstrating correct laboratory technique for filtration under reduced pressure
• Technician preparation of filtration apparatus
• Ensuring airtight, stable setups that improve safety and consistency

Practical, reliable, and essential for filtration work, this Rubber Cone Adapter provides a simple and effective solution for creating secure seals between Büchner funnels and laboratory flasks.