Endpin

The endpin or spike is the component of a cello or double bass that makes contact with the floor to support the instrument's weight. It is made of metal, or in some cases wood or carbon fiber, and is extensible from the bottom of the instrument, and secured with a thumbscrew. Most bass clarinets and contrabassoons also have a similar fixture.

Read more about Endpin:  Types of Endpins, Endpin Anchors/holders/stoppers, Endpins and Flooring