Duplicates are produced from silver (not silver-plate, but 100% silver and don’t contain any copper). The image on the reward reduplicates the original one by 95%, the differences are nearly visible, and are due to objective impossibility of 100% reduplication identity. Weight, diameters are by 95% repeat the original rewards.
We often don’t have an opportunity to buy certain rewards that exist only in a very limited amount. That’s why these duplicates would perfectly suit your collection.