Tripod screw 1/4 on the camera shoe.
Bought here: http://ali.ski/Wy0LOe
Interesting accessory for the camera under the "hot shoe" -statious screw 1/4. You can hook it all. that has a thread 1/4, and this is the most common size. Backlight, a microphone, an action camera, a video camera, an additional camera - holds tightly and reliably. Made entirely of metal aluminum. I recommend.