Czech tale "Dlouhý, široký a bystrozraký" by Karel Jaromír Erben, it has also other names:
"Long, Broad and Sharpsight"
"Longshanks, Girth, and Keen: The Story of Three Wonderful Serving Men"
or it is similar to "The Six Servants" by Grimm
It is about three servants helping prince with his quests of finding his enchanted princess (enchanted as an oak nut, gemstone and ring). Long can make himself very long, Broad can go very wide, Sharpsight can destroy rocks without his eye cover or he can see everything through his eye cover.