These milk collection shells are great! Once you can start to remember to put one on prior to feeding bub it is great at catching the let down from your other breast.
There is a small hole at the top of the shell for pouring out the milk. If you accidentally forget you are wearing the shell and you lean forward you may accidentally tip out your recently collected milk.
The shells can hold approx 30ml each; I have found I needed to lean forward slightly before removing the shell which is harder to do in the early days as bub has usually fallen asleep on you.