Needless to say, most ordinary beds can be used quite successfully for bondage with little or no modification. Iron bed frames are however particularly suited due to their inherent strength and large number of attachment points. As well as the high street bed retailers there are specialist BDSM equipment suppliers selling bondage beds. Most are designed to be installed in a normal bedroom and usually look quite innocent (if a little gothic) to the casual observer. It is also possible to get beds with cages built into the base of the bedframe where the submissive can be kept while the top sleeps above.