Modifry Product's custom-designed speaker spacer rings allow easy installation of most 6.5" and 6.75" speakers with a cut-out dimension over 5.4 inches. These are CNC-machined in our shop from high-density urethane, which has many benefits over wood-based products. In addition to a 66% weight savings vs MDF, this material is dimensionally stable, dampens vibrations better, and is impervious to water. And because it's not as hard as MDF you can mount your speakers without the need to pre-drill pilot holes when using the self-starting deep-thread screws that we supply. If you need more than 4 screws for each speaker we suggest you purchase an extra pack of 8 screws from us, as not all "wood screws" will hold well in this material.