These fit the Yongnuo 600ex-rt, 568ex, 568exii, 560, 560ii, 560iii, 560iv, 685, 565ex, 565exii

Canon 600ex-rt, 580exii, 580ex, 

It will fit some nikon flashes as well. 

Flashes with smaller heads may not fit properly. But,  wrapping a coozie or gaffers tape around the flash head can remedy that. 

This softbox is 25inx25in. It unfolds like an umbrella and is very easy to use. It comes with the attachment for you to use with your stand. The Speedlight slides into the holder so there is no pressure on the hot shoe. 

There is a baffle inside that allows you to have softer light with fewer hot spots than with a shoot through umbrella.