Sweetened condensed milk is made from pasteurized whole milk that has had 60% of the water removed by heating the milk and concentrating it and then sugar is added. The resulting liquid is quite thick and it is used as a cooking ingredient for pies, fudge, flan and other desserts. The most popular brand in the U.S. is Eagle Brand. Their ingredients are only milk and sugar.
This is really the same product as sweetened condensed milk except the ingredients frequently contain items other than sugar and milk which may include: vegetable oil (palm oil), whey powder, skim milk powder, maltodextrine, carrageenan, salt and lactose. Common brands include Jans Sweetened Condensed Creamer ( Leche Condensada Azucarada Llenada). Typically sweetened condensed "creamer" is manufactured in various Asian countries.