The biggest little block in the nanoverse. Build your very own Small Clawed Otter with the smallest building blocks in the world! nanoblock building sets contain micro-sized building blocks with the smallest piece a mere 4mm x 4mm x 5mm. Challenging and fun for all the construction enthusiasts in the family, nanoblock building blocks and building sets lets you build in greater detail than ever before! Over 100 different sets to collect sets for many skill levels.