Kagamine Rin and Len
From Vocaloidism Wiki
Kagamine Rin/Len (鏡音リン・レン, Kagamine Rin/Len) is the second installment of the Vocaloid2 Character Vocal Series, a female voice (Rin) and a male voice (Len) released on December 27, 2007.
Both characters are voiced by the Japanese voice actress Shimoda Asami. They were designed by the Japanese illustrator KEI, who had previously created the design for Hatsune Miku. Rin and Len's family name was created by combining "Kagami" (鏡, Mirror) and "Ne" (音, Sound). As such, Rin and Len are created to be opposite genders of the same character. Their given names are a pun on left and right. Despite the double voice banks, Rin and Len sell at the same price as Miku.
The updated edition of the software, titled "Act.2", was released on July 18, 2008. The update featured improved voice banks for both Rin and Len, which results in smoother vocals when used. Owners of the original software had the chance to obtain an Act.2 disc free of charge. All retail versions of the Kagamine Rin/Len software were eventually replaced with the Act.2. It retails at the same price as the original.
