I rent a hospital grade pump from you and have purchased 36in shells from you for it as these are the best fit for me. When buying my own pump I would have liked to have received an extra set instead of more of the sizes that were no good to me in the first place. I rang to see if this was possible and was just told that I could buy them on your website. The person dealing with my request was not at all helpful and seemed quite uncaring like she really couldn't care less. I think that you should give the choice of sizes instead of assuming that the ones you include will do everyone. Now I have 2 sets of useless attachments, such a waste really. On the other hand the website was easy to use and the delivery was prompt. The pump is well packaged and in good working order.