Sensory rooms for ASD?

[extremepie]

I've been thinking about trying to put together some sort of sensory environment for DS2, who has ASD.

Thing is, and I feel a bit stupid saying this but, what is it about them that is good?

What are the benefits of having one, what is the best stuff to have in them, etc?

Obviously I'm guessing that it depends on what your child's individual likes/dislikes are but I'm just after a general guide on what I need to know before I start spending money!

Generally DS seems to be pretty 'understimulated', he loves the bright colours, lights, noises, etc but I want to make sure he gets the most out of whatever space we make.

Any advice very welcome!

Hi, We don't have a sensory room as such but dd is also 'understimulated', I read somewhere that the term is hypo sensitive.
We got her a bubble tube for Christmas as she does have a playroom so put it in there as opposed to bedroom which is meant for sleeping iyswim? She also has a rainmaker and lots of tactile stuff to help with sensory issues.
The benefit inher case seems to be a soothing one.
There are quite a few websites around with different kinds of sensory toys. I used this one.