It is the simplest grid to do. It may be of iron or aluminum, the latter being preferred because it does not rust, and is lighter.
Tubes in parallel, equidistant or not, or in a grid, subject to the ceiling by means of threaded rods are placed.
You can make a primary grid attached to forging, or supplement it with a secondary grid under it, with pipes subject to the primary by double claws, so releasing the grip, or loosening them, you can vary the position of the secondary.
This type of grid is the most economical and is used in heights up to 4 m. Where many changes will not be necessary in lighting, or large suspensions, such as pantographs or hoists.