These boots appear to belong to two different pairs, but are indeed a set of their own. When worn together they allow the wearer to swap the locations of two individuals with one another.

Wonderous item, Legendary (requires attunement)

While wearing these boot you gain the following benefits

Speed Increase - Your total movement is increased by 10.

Movement Pool - You have a pool of distance that equals your current movement score x 4. Distance drained from this pool replinishes after a long rest.

Swap Places - You can as a reaction swap the places with and ally or swap the places of two allies with one another. You are limited to your Movement Pool, and the distance between the targets is drained from your pool. Ally must be willing or unable to resist the swap.