Original sentence: It uses flash memory, like the iPod shuffle, but with a miniaturized version of the display screen and "click wheel" found on the iPod classic.The first generation model was introduced in 2005.The model has been updated twice since then.The nano was launched in two colors (black and white) with two available sizes: 2 GB (roughly 500 songs) for US$199 and 4 GB (1000 songs) for US$249
Edited sentence: It was intended to replace the iPod mini, which was discontinued on the same day.The  nano was launched in two colors (black and white) with two available sizes: 2 GB (roughly 500 songs) for US$199 and 4 GB (1000 songs) for US$249.The battery and other internal parts were also reduced in size compared to the mini.The first generation model was introduced in 2005 combining features of both the iPod shuffle and iPod classic.The nano uses flash memory, like the iPod shuffle, but with a miniaturized version of the display screen and "click wheel" found on the iPod classic.The replacement of the mini took Apple-related websites and the press completely by surprise since, although there were rumors about a new flash memory-based iPod, there was no prior notice of the popular mini being discontinued.The screen also shares the same resolution as the classic