The vacuum stretches the breast tissue gently over a sustained period of time. When cells are stretched, they respond both by swelling temporarily and by replicating until, eventually, the cells divide to accommodate stretch force. The new tissue is identical to the woman's original breast tissue, and feels the same both to her and from the "outside." Using it longer and more often- does produce faster results. Pump to a comfortable pressure and hold that for 10 to 15 minutes on each breast twice a day. Do not over pump, if there is pain or discomfort then release the pressure. Cup diameter 12cm.Package include:2x Cups,1 x Cup,1 x Manual