It is a socket which is used to grip a drilled hole in a stone by expanding, as the bolt is screwed into it.

Any bolt similar to the "Brohard Expansion Bolt."

a bolt that has an attachment that expands as the bolt is driven into a surface

a socket that grips a drilled hole in stone by expanding as the bolt is screwed into it.

An anchoring device (based on a friction grip) in which an expandable socket swells, causing a wedge action, as a bolt is tightened into it.

A bolt used to anchor lumber to masonry walls. The jacket of an expansion bolt expands to grip the side walls of a pilot hole due to wedge pressure at its base or the wedge force of a bolt screwed into it.

Bolt and expandable sleeve which is used to fasten masonry by inserting the unit into a drilled hole in the masonry and then tightening it which causes a wedge which expands the sleeve into the hole for a snug fit.

a steel stud drilled into the rock; used mainly in sport climbing for protection where cracks aren't available.