2024 rules reference for Horseshoes of Speed.
Wondrous Item
These horseshoes come in a set of four. As a Magic action, you can touch one of the horseshoes to the hoof of a horse or similar creature, whereupon the horseshoe affixes itself to the hoof. Removing a horseshoe also takes a Magic action.
While all four horseshoes are attached to the same creature, its Speed is increased by 30 feet.