Nokia WR d3/d4 are directional and WR a3/a4 are asymmetrical 

The clue is in the name d3/d4 = directional and a3/a4 for asymmetrical. WR is winter radial.

Bridgestone tend to put an A at the end of the tyre code ( RE050A ) if it is the asymmetrical version.

 

Thanks AG Falco

Vredestein Quattrac5, albeit only all seasons, are assymetric and bi directional. 

I have used the Nokian WR A3 - they were fine in snow - and have swapped my spare to Continental CONTIWINTERCONTACT TS830P M+S, which is asymmetric. My current winter tyres are directional but I am looking at getting asymmetric ones next time as I like to swap them front to back and crosswise.

I have weighed my "standard" spare - ContiContact summer tyre 205/55-16 on a steel wheel - and my 205 winter alloy wheels and even though the winter alloys are not much lighter they are still a little lighter.

 

On 03/11/2018 at 18:04, 26DIPP said:

and even though the winter alloys are not much lighter they are still a little lighter.

Interesting fact.  I recently put together a full sized 16" spare from a genuine 7J VW rim and a 215/60 R16 winter tyre and when I was carrying them to the fitter I decided the tyre was heavier than the rim by a noticeable bit.  So maybe tyres should be listed with a weight online as well as rims.