Kagamine Rin & Len (鏡音リン・レン), codenamed CV02, are Japanese vocals developed and distributed by Crypton Future Media, Inc., and were initially released in December 2007 for the VOCALOID2 engine. They are the second set of vocals for Crypton’s Character Vocal Series and are both Character Voice VOCALOIDs. There have since been numerous installments such as additional voice banks dubbed ‘Append’, an update to the VOCALOID4 engine, and an English vocal. On August 30 2024, a refined and retuned edition of Kagamine Rin & Len’s original VOCALOID4 (V4X) voicebanks, titled Kagamine Rin SP and Kagamine Len SP respectively, were released for the PIAPRO CHARACTERS SUPER PACK, a set of Japanese voicebanks developed for the Piapro Studio for V4X and VOCALOID4 engines. This release was noted to improve Rin & Len’s overall balance of tone and pronunciation.