The "120 ml" cups are a bit too big to start pumping without warmup. I got the size below "105 ml" which are the same diameter as NB's standard large cups, but contoured and a bit taller. They aren't of the same quality as NB, and some sharp edge (remain of the molding process) on the rim had to be filed. Then they fit better on ribs and I have to pump less to avoid stopping blood circulation. Also ordered the matching 6mm ID hose which is quite long and has end connectors which can stretch enough to insert the 7 mm white NB pump, and bigger cups (150 and 180) to pump my butt/hips.