Dynabolt is a Ramset trademark that became generic for sleeve-style mechanical anchors. The fastener has a bolt or stud surrounded by an expanding sleeve. You drill a hole in concrete or brick, push the dynabolt in, and tighten the bolt. The sleeve expands against the hole wall, gripping it by friction.
Dynabolts are quick (no resin, no cure wait) and reliable for medium-load applications. Pull-out strength is significantly less than a chemical anchor of the same diameter, so they're not the structural choice for the highest-load fixings.
Gate-trade uses: fixing wall-bolted posts to brick or concrete walls, fixing photo-eye and keypad brackets to existing structure, fixing gate-motor mounting feet to a small concrete pad. Common sizes are M8, M10, and M12, in lengths 50 to 120 mm.