重音テト
Kasane Teto (重音テト) is an UTAU character; UTAU is a freeware vocal synthesizer designed for singing. Teto was originally created as a joke of sorts on a forum, but she ended up becoming very popular, even officially recognized by Crypton, and appears in things like the Project DIVA games. Due to her popularity, she is essentially the face of the UTAU program. She is owned by TwinDrill.
リバーシブル・キャンペーン
Reversible Campaign is a song by producer DECO*27, originally made using Hatsune Miku. This outfit is based on how Teto appears in her version, depicted by artist おね美, which you can see here.
These cuffs were made to match the Reverse Campaign Teto outfit. They're simple, bright silver, shiny, broken handcuffs - there are still a few chain links attached to each cuff. Super cool!