Freejack 7 Port Rectangle Canopy mounts to a standard 4 inch junction box with round plaster ring or an octagonal electrical box (not included). Drywall anchors included for additional support. Includes electronic transformers which fit inside canopy and features seven Freejack ports. Dimmable with an electronic low voltage dimmer, sold separately. Compatible with both halogen and LED Freejack pendants and heads.