A burette clamp extension double key is a laboratory tool used to hold burettes or other cylindrical objects such as pipettes or thermometers. It is made up of two metal rods with one rod attached to a clamp and the other rod attached to a double key.

The clamp is used to secure the burette in place while the double key is used to adjust the height of the burette. This tool is typically made of durable and corrosion-resistant materials such as metal or plastic.