The mouthpieces are delivered hygienically packed individually, and can also be unpacked and used, without having to touch them. The return valve works fine, but the mouthpieces do not fit exactly to my ACE DA 7100. The mouthpieces can be introduced, but fall in an inclined position just out of the machine. The normal drunk but always want to take the thing in hand. If then falls out the mouthpiece that is simply unacceptable.
