Extraction , need to get vent through roof tile

Hi, Next part of my garage conversion I need to get ventilation from my WC/shower to the outside world, and in my case this is best through the roof. What is the best method to achieve this task please? Are there purpose vents, I thought I saw someting once which is like a raised roof tile with pipe attachment, doesn't let condensation back down pipe. Any ideas appreciated.
thanks
KS

There are plenty of vent tiles/Slates on the market You will need to know which tile you have and specify it's for an extractor then you will likely be sold an adaptor as well.
look at KLobers site

Great thanks, found the site www.klober.co.uk. I just needed pointing in the right direction, and that's what you've done. thanks. When you only see the big diy stores you forget about the specialists roofing chaps who will have far more knowledge... ta
KS