If you've ever bought green gages from a supermarket in the UK or western Europe, they are almost certainly Reine Claude de Bavay. Don't worry if you were disappointed with the flavour - you can solve that problem by growing your own!
Whilst a purist might prefer Old Green Gage, Reine Claude de Bavay also has the distinctive gage flavour, but is easier to grow. Cropping is more reliable, but as with all gages, not heavy.
The fruit is medium-sized, and green/yellow when ripe. Rated by Victorian author Hogg as "a first rate dessert plum of exquisite flavour".