What is the little hardware button on a clip that is slid into a tube and snaps 2 tubes together called?

Question

I have seen it on aluminum tubes for bicycle trailers, outdoor gear, collapsible shovels, baby jumpers... the two tubes are fitted so one slides over the other and this piece of hardware locks them together.

The button then snaps through a hole on the larger tube when the two peices are joined.

Answer 1

Various names: "Spring Pins", "Spring Plungers","Ball Nose"
depends on where and how they are used. Most of these are used to lightly hold something in position like a cabinet door.

But I think this is what you are looking for....

The McMaster Carr catalog calls them by the technical name
"Quick-Release Button Connectors for Telescoping Tubing"

Part Number 92988A730