The Nexpand cable rings are a high quality product made out of a combination of glass fiber reinforced with nylon that ensures a solid product with a certain degree of flexibility but nearly impossible to deform or even break! The brackets can be mounted without the use of any tools on the Nexpand cable trays and on the vertical cable management profiles (ordered separately) that attach to the VMRs, if you opt for the ring with bracket, it enables the possibility of mounting them onto the height posts. They come in a set of 10 pieces.