I bought this bag to hold primarily my Samson headphone amp, plus various other bits and pieces, and to fit inside my existing UDG XL backpack which holds my analogue mixer, so everything is tidy, packed in tight, and simple to carry around town using public transport.
There are several other bags about the right size, and considerably cheaper, but for the extra £30 - £40 I get a much better padded bag, plus all the excellent UDG velcroed and flexible insert pads, and it's these that make all the difference as they enable you to pack everything in tightly so nothing can bounce around during transit.
One detail: there are contradictory listings online regarding the height (or depth) of this bag - having measured it it's 12cm.