Here's a free alternative.....
http://www.shower-smart.co.uk/
dodle to fit!
Saddo that I am I tested one of these in the uk basd on our water pressure by filling a bucket for 30 seconds with the showersmart and then without it. With the sowersmart fitted it only used half the water as without it.
Fitted it to our apartment in Spain fully expecting my wife to say that pressure is rubbish, particularly as we have a very good power shower at home and with her long hair she does like to give it a good rinse! but no complaints and it has stayed on.
Also, last year we invited out my in-laws so had 3 kids and 4 adults all getting ready to go out at the same time. With the showersmart attached we all managed (with me going last) to have a warm shower (didn't need any hotter as it was mid summer) and the water lasted for all of us. Not so sure the hot water would have lasted if the shower smart wasn't fitted.
I had ordered the ecocamel and tested but the showersmart did just as good a job but for free!