"Rin Rin Signal" is Signal-P's first work, which became notable to the point that that word "Signal" became his P name. The song has over 710,000 views on Niconico and over 1,000,000 on YouTube. On December 28, 2007, a day after the Kagamines were released, Signal-P uploaded "Rin Rin Signal test version", a short version of the song, and he uploaded the full version a week later on January 7, 2008. Rin continues expressing her seemingly endless choice of words for her love for Len until he finally admits he can hear her signal, implying he loves her the same.