Cavity fixings are braces that allow you to attach something to a wall that is hollow or has open space behind it. These mechanisms protect your wall and the item you're hanging. When choosing cavity wall fixings, you want to use care, so you choose one that provides enough strength to support your object without causing damage to the wall.
When hanging something on the wall, you need to have it braced, so the screws don't pull loose. No one wants their TV falling to the ground in the middle of the night. Ideally, you'd mount your screws to a stud in the wall. But many times, the walls in your home will have a gap behind them, limiting your options on screwing into a hard, stable surface for support.
Cavity fixings can solve the problem of not having something solid to attach your screws when mounting an object. These devices go into the wall and secure to the backside, anchoring the screw, so it doesn't budge.
These mechanisms aren't just for hollow walls. You can also use them on soft materials to offer structural support, such as plasterboard or hardboard.
Cavity fixings usually have some housing that you insert into the wall before adding your screws. Once inserted, your screw is added into the middle of the cavity fixing.
The design can vary from a cone-shaped piece of plastic with threading similar to a screw-like the Forgefix Nylon Speed Plug to heavy-duty metal fixtures with a broader outer case that secures to the inside of the wall to provide support such as the Timco Zip-Fix.