I bought these a while ago and loved them. I've since gone back to by more because I find them so useful. It's hard to wash and dry your hair in an orderly time when it's as long as mine is. So I quite often go days on end without washing it. The Lee Stafford Dry Shampoo works wonders. It comes out quite white on your hair but it quickly soaks up all the oil and leaves it looking freshly washed.
I've not used the dehumidifier a lot, but it did prove useful when I went to Rarotonga a couple of months ago. It stops your hair from frizzing up too much when there's a lot of moisture in the air. Where I live it isn't very warm at the moment, but on nights where i've straightened my hair and it's raining, i'll probably find it useful.
Another brilliant thing about these is the smell! They smell delicious, not like aerosol or alcohol or any chemicals. A big thumbs up from me.
They're super easy to use for those who haven't. Just spray holding the can roughly fifteen centimetres away from your hair, avoiding eyes, and you're done! If it comes out white - like I mentioned - then just run your fingers through your hair.