If you are looking for the series itself or the physical soundtracks: Sorrow | Speed Grapher OST

The music box melodies are a central emotional theme in the series, composed by and Shinkichi Mitsumune . These tracks are available on official CD releases:

: Some sellers offer USB-rechargeable music boxes where you can upload the specific MP3 file of "Memory of Music Box" to play when opened.

: You can find the full collection of tracks, including "Sorrow" (an instrumental piano/music box piece featured in episodes 10 and 23), on various music platforms or as part of Limited Edition DVD sets . Custom Music Boxes

Since an official "Speed Grapher Music Box" was not widely manufactured as a collectible, many fans turn to custom services. Retailers on Etsy and eBay specialize in creating that can be programmed with custom anime songs.