You will find them in some Walmart/Carrefour, and anywhere else that sells bathroom stuff.
Don't waste your time, or money. They are a bit of a con. They do not increase flow. They pulse it with some kind of spinner in the head. Arguably they increase pressure momentarily, but then decrease it momentarily. I couldn't feel any difference really. The volume per minute is the same.
Ah ok, thanks DanDare. Good to know before I "googled it". Appreciate it.
These water pulsars are another obstruction and reduce the pressure even more. They only work properly if you have a surplus of pressure so are unsuitable in your situation.
i used to live in a low rising unit with a solar heating system, my experience with an old solar system is, short of getting a tradie to reverse flush the system, the hope of getting higher/normal pressure from the gravity feed thingie is remote.
You can install a pressure regulator, if you don't have ask your plumber to set the regulator to increase your hot water pressure