The Viltrox JY-680 is an all manual speedlight designed for off-camera “strobist” use. There are no TTL or automatic modes, but you do get two optical slave modes and manual adjustment down to 1/128 of full power.
Taking a look at the body of the device, you may notice that the JY-680 is the spitting image of Canon’s 580EX II. One of the current trends in Chinese flashes is to make them look like the Canon & Nikon flagship speedlights 580EX II and SB-900. This isn’t purely Shanzhai thinking though – it means that existing flashgun accessories, such as diffusers, will still fit these new lights.
The Viltrox JY-680 can swivel 180° right and left and tilt upwards 90°. You can just push the head to turn it – no need to squeeze a release button.