A hard, rigid set of balls with a firm jelly coating, and small, slightly raised white stars. All one piece, with no obvious seams and a bridge connecting the balls, allowing easy cleaning. The Duo balls are weighted with steel balls, giving comparatively strong vibrations, but are quite quiet due to their soft coating. A black nylon cord is attached for easy removal. Can be used both for foreplay, a bit of fun, or pelvic floor exercises.