Help! Advise choosing cheap digital

Hi everyone I'm new here, I'm looking for advise choosing a cheap digital watch?

It is for the gym and so I would like a stop watch feature and water proof (just enough to swin 10m or above is fine) needs to be tuff.

I have seen a lot of decent looking watches but my main concern is a good sterdy watch that isnt going to die, or one atleast with a warranty.

I'm looking to spend around £20 (cheap I know) but I only want a decent built watch with a stop watch feature not too much I'm asking for and I dont care what the watch looks like.

All suggestions are welcome and thanks guys for any advise ya can throw my way or just for reading this :-!