The Seven League Boots are a pair of enchanted boots.
Seven League Boots are a famous magical artifact featuring in fairy tales, being a pair of boots which can resize themselves to fit anyone and allow their wearer to make humongous strides (hence the name). In 1969, Gyro Gearloose used his Fantasy Finder to meet Puss-in-Boots, who ended up gifting him the Seven League Boots, which he brought back to Duckburg for testing.
Behind the scenes
The Seven League Boots appear in the 1969 story The Golden Apples. Notably, in the real world, the Seven League Boots play no part in the fairy tale Puss in Boots; within Perrault's body of work, they are instead featured in Little Thumbling, although this is far from the only fairy tale in which some variation of them appears.