Lansium domesticum is a tree native to Malaysia and Indonesia . This tree is now widely grown in tropical regions for its sweet fruit, known variously as the langsat, lansa, langseh, langsep, lanzon, lanzone, lansone, duku or kokosan. The skin is yellow to brown and often spotted, with a smooth and waxy texture. When peeled away, it reveals separate slices of sweet translucent meat, which contains bitter seeds that are not eaten.

Source: http://en.wikipedia.org/wiki/Lansium_domesticum