A plastic sprayer is what I first bought and lasted 18 months, continually replacing seals and blocking.
I then bought a spraychem stainless steel unit 10 liter very good and still going strong £140 inc brass handle and lance. I also have a Gloria sprayer 5 liter for protection, but will do for anything these are the best and most expensive due to build quality.
Always use brass fan jets as plastic ones damage easily when trying to unblock.
The next one I will get will be a good quality electric sprayer just because it will save time pumping up and also I am becoming lazey in my old age
John