Embodiments of U-frame padlocks are described, the U-frame padlocks comprises a threaded bush disposed coaxially with a locking bolt or an arm of a U-shackle bolt to secure the padlocks onto an eye bracket at a point of use. Preferably, a U-frame body of the U-frame padlock is made of a swivel body connected by a swivel pin to a mounting body. In some embodiments, a pivot axis of the swivel pin is substantially perpendicular to a longitudinal axis of a locking bolt; in other embodiments, the axes are offset. In use on a 2-leaf gate, the swivel body can thus be turned through an angle so as not to obstruct a moveable leaf of the gate or passageway through the gate. These padlocks can be wirelessly controlled via an application in a smartphone.