This is a 12 sided D6 spot dice. 

It has 1-6 twice on the dice making it a six sided dice but on 12 sides.

Made from high quality Zircon Glass with the numbers are laser engraved and hand painted in ink.

These are made for us at TheDiceShopOnline and are the best we have ever seen and are cut to a very high standard each set and dice is unique and vary slightly from the picture.