Help identifying watch

I'm hoping someone can help. We are trying to identify this IWC watch. It only has a case number on the back which is 2586431. No other markings. It was purchased about 15 years ago.

Thank you if you can help.

We'd need to see an image. Here's how to post one:

Thank you Michael. I copied the IMG code from PB but it seems not to want to appear. I'll try again -

Clicking on the Preview Tick is not showing me a preview of my posts either.

Let's see if this works...

Showy --you have a reference 3513 Portofino with a military or Mk 11 dial. You can find out some more by searching our archives, via the magnifying glass on the upper right.

Thank you so much Michael. I spent ages going through the IWC workbooks and I couldn't find it anywhere. Off to search your archives for more info. :)