I am very dissappointed with the Ardo Carum hospital grade pump. I have the Medela swing Maxi at home but I was looking for a more efficient, faster expressing experience. I received the carum pump on Tuesday with the standard 26mm shells. I tried expressing but after 45min I only managed to get 40ml of breast milk from both breasts. The vacuum is minimal compared to the Medela swing maxi (even though I had set it to the maximum). On Wednesday, I requested smaller shells as the 26mm were to big for me and may be the reason for the poor vacuum. The shells arrived on Friday. I tried expressing on Friday and Saturday and the performance did not improved. Please note that I normally express 100ml of breast on a 20-25min period using the medela swing maxi. I'm not sure whether the pump I received is faulty or the pump sets have an air leak, but my experience with this pump is very disappointing. WRT Ardo Medical service, the pump arrived promptly the next working day after ordering, packaging was excellent. When I requested the smaller shell size, I was a bit shocked that the new shells were not included in the hire agreement as I couldn't use the pump with the standard shell size. Ardo then agreed to send this for free but I had to pay for the delivery which I accepted. The shells took two days to arrive which means that in 5days of the rental period, I was only able to express 2days