Kagamine Rin & Len (Japanese: 鏡音リン・レン), sometimes referred to as Rin & Len Kagamine, are humanoid personas voiced by a singing synthesizer application developed by Crypton Future Media, headquartered in Sapporo, Japan. They use Yamaha Corporation's Vocaloid 2 and Vocaloid 4 singing synthesizing technology. Their voices are sampled by Asami Shimoda. They have performed at live concerts onstage as animated hologram projections