Kagamine Rin & Len, 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. Their names are derived from the concept of 'left' and 'right', like in stereophonic sound. Their surnames came from the Japanese words for "mirror" (kagami) and "sound" (ne).