Really great, with small improvement suggestions

Our son was first fed as a premature baby with the bottle. However, I wanted to bring him necessarily to his chest. Thanks to a lactation consultant it worked, at least, that he is teilgestillt.
Unfortunately he hampelte at the breast around often because it indeed means more work, with difficulty to tap into the milk from the breast, rather than from the vial (Avent, Nuk, MAM - all tested) to let druckbetanken. From the bottle the milk runs out so formally and our impatient Junior inhaled the bottle downright - with corresponding air in your stomach.
This is what I wanted to change. So I came up with the vial of Medela Calma with attachment.

And I'm thrilled! The milk runs only when the baby makes a vacuum, as it must do so on the chest. So there must be employed by the dairy here. When baby was out quickly how it works. It is nice that the bottle may fall over and it runs not out - unless the baby has just drawn something in the antechamber, the small amount may then leak.
Disadvantage is that you can not do the usual heat test in these vials rausträufeln on the wrist.
We have become accustomed to mix together the water into another bottle to make the wrist test and then to pour the water into the Medela bottle, then mix in the powder. Initially used to, but after 1-2 times you get the hang of it and is quite fast. And you look at it like in buying, since you just wanted that the child has to form a vacuum.

Even with Calma my son (now 8 weeks in Calma past 2.5 weeks use) now rather quickly when emptying the bottle. But the Medela bottles in comparison with the other brands (Avent, Nuk, MAM - all tested) is absolutely the best ventilation, as does not hold any other bottle. Thus, the air in the stomach is significantly less.

The vial is easy to clean and the material is very high quality.

Point deduction is available for the thread of teats and bottles, which is very tricky - if you do not set each other accurately, then you screwed diagonally together. This sucks then already when it repeatedly does not work and actually got to be quick. Since Medela could really make improvements.
Even when the covers, the lock only in a certain position. This is annoying and unnecessary difficulty to stressed parents but the work.