Antigua and Barbuda, Aruba, Australia, Austria, Bahamas, Bahrain, Bangladesh, Barbados, Belgium, Belize, Bermuda, Bolivia, Brazil, Brunei Darussalam, Bulgaria, Cambodia, Canada, Cayman Islands, Chile, Colombia, Costa Rica, Cyprus, Czech Republic, Denmark, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Estonia, Finland, France, French Guiana, Germany, Gibraltar, Greece, Grenada, Guadeloupe, Guatemala, Guernsey, Honduras, Hungary, Iceland, Indonesia, Ireland, Israel, Italy, Jamaica, Japan, Jersey, Jordan, Kuwait, Latvia, Liechtenstein, Lithuania, Luxembourg, Macau, Malaysia, Maldives, Malta, Martinique, Mexico, Monaco, Montserrat, Netherlands, New Zealand, Nicaragua, Norway, Oman, Pakistan, Panama, Paraguay, Peru, Philippines, Poland, Portugal, Qatar, Republic of Croatia, Reunion, Romania, Saint Kitts-Nevis, Saint Lucia, Saudi Arabia, Singapore, Slovakia, Slovenia, South Africa, South Korea, Spain, Sri Lanka, Sweden, Switzerland, Taiwan, Thailand, Trinidad and Tobago, Turks and Caicos Islands, United Arab Emirates, United States, Vietnam
There is no U2/Tristar IC in the iPhone 4S. All of the charging functions are handled by the PMIC (U5). Tristar was developed and included in the iPhone 5 along with the Lightning connector versus the older 30-pin connector.