Apple currently controls these centers, although some operate as drop-shipping facilities for major cell phone companies, which account for the vast majority of iPhone sales. Apple currently produces and stocks a limited quality of iPhones at any time, meaning that when a new phone is introduced, limited quantities are available due to the rapid-market strategy used by Apple. The distribution stage of the product lifecycle is managed by Apple's headquarters in the United States, but the product is distributed worldwide. Marketing and customer service for the product are also handled directly by Apple. These marketing and promotion strategies should be carefully considered in order to clearly and clearly provide the best qualities of the team and product descriptions.