This contribution presents a study examining five different interaction methods for manipulating objects in augmented reality (AR). Three of them were implemented on a smartglass (virtual buttons, swipe pad of a smartglass, remote control via the touchscreen of a smartwatch) and two of them on a smartphone (virtual buttons, touch interaction). 32 participants were asked to scale and rotate a virtual 3D object. We studied the usability of the interaction methods by measuring effectiveness, efficiency, and satisfaction of the users. The results of the study showed that smartphone interaction is superior to any of the studied smartglass interaction methods. Of the interaction methods implemented for the smartglass, the interaction via smartwatch shows the highest usability. Our findings suggest that smartwatches offer higher grades of usability when interacting with virtual objects rather than using the swipe pad of the smartglass or virtual buttons.