This foam has like the name suggests, a special ability. It allows light to pass through. The thicker the LED foam, the more it diffuses and the stronger it is. But a higher thickness also results in a lower brightness of the light.
It’s possible to sand, heat and glue (note: super glue can give reactions) LED foam, just like regular foam. It is recommended to paint this type of foam with an airbrush or with a sponge using transparent paint.