This is a simple cover for the FIIO RR11. The device slide in the cover but you need to add some internal thickness because i could't make it so thight or it would scratch the device. I used some trasparent tape applied on internal walls. I suggest to use some supports, in fact there are some bridges, in particular the one of the logo is a little bit wide so if you dont do a support it could not be so good to see on the external.