This little carrier is a bless if you just carry you acoustic around and want to play with picks. I always use picks and always forget to pick them up but you can stick this to the side of the guitar and it looks cool too.
The quality is good, just don't expect it to last for years with daily use, that's because of the springers that push the picks outwards to create tension.
It can easily be put on the guitar because it has glue on the back and can easily be removed too if you want, just make sure that when you remove it you take care and don't do it quickly.
Any pick size will fit in it, and around 10 picks at a time. Yes you will have to remove the top ones in order to reach the bottom ones but it is very handy.
I used it last time and honestly for 5 euros, I would pick this up right away. Don't buy the ones that stick on the nut of the guitar because those usually ring out (I don't know maybe mine was just bad) and this looks way cooler anyway on the side.