One of the regular deliverables we produce at Globoforce are handover designs for our front-end developers. Most of them work in Belarus so it's essential they have detailed specifications to work from. Below you'll find an example I did recently for an award card I had designed. I use the specification style that Google use which I find very quick and intuitive.

Nowadays we've started to use Zeplin integration with our Sketch files which makes things even easier, but it's still an essential skill for any UI designer to have.