EQ Acoustics Classic Wedge 60 Tile grey

I used only 6 of these to soundproof my flats apartment room. I also used 3 of the small ones "EQ Acoustics Classic Wedge 30" and that pretty much did it. Only minus with these is that they are hard to get keep o nthe wall. I'm still testing a way to keep them on the wall and so far they have dropped couple of times so I still need to come with a good way to hang them. I would give 5/5, but since they are hard to keep on the wall since I haven't found good way yet I only give 4/5.