Swim cap for hair extensions

[Pandorapitstop]

I'd love to start going swimming and to aquafit classes, but I've got thick hair ( extensions), and it's such a palaver to wash and dry.
Is there a swim cap which is watertight, or is that expecting too much?
I suppose a shower cap type thing might suffice for an aquafit class, as that would be more to just prevent splashes.

This type?

www.amazon.co.uk/Swim-Elite-Silicone-Dreadlocks-extension/dp/B07LFCNC2T/ref=asc_df_B07LFCNC2T?tag=bingshoppinga-21&linkCode=df0&hvadid=80264405731090&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4583863981560376&th=1&psc=1

There aren't any that are watertight. I have long extensions as well and the best way to do it is wet your hair completely to avoid the chlorine soaking into your extensions, then put a silicon swimcap on over. Can't avoid the washing/drying but at least it protects your hair.