The light switch is designed to fit over the standard United States light switches. I designed this using the reference photo and dimensions above. The Lightswitch cover's overall length is 2.75 x 4.5 x .26 inches.
In order to add depth to the flowers, a few of them had to be floating above the light switch. From the looks of it, none of the flowers are floating 100%; there is always a little bit of flower connected to another flower secured to the switch cover. Supports under the floating flowers should not be too visible.