Sylvanas' Music Box
The {item:inv_misc_enggizmos_18} Sylvanas' Music Box is a Binds When Used toy obtained from the Shadowmourne legendary questline in Icecrown Citadel during Wrath of the Lich King, rewarding the player with a music box that plays Lament of the Highborne.
The 
Sylvanas' Music Box is a Binds When Used toy obtained from the Shadowmourne legendary questline in Icecrown Citadel during Wrath of the Lich King, rewarding the player with a music box that plays Lament of the Highborne.
Guide awaiting review
Obtain Shadowmourne First
The questline requires a player in your raid to wield 
Shadowmourne. This legendary two-handed axe is the key to triggering the special loot from the Lich King.
Defeat the Lich King
Enter Icecrown Citadel and defeat the Lich King. When killed while a Shadowmourne wielder is present, the Lich King drops an additional Unsealed Chest alongside the normal loot.
Bring Chest to Darion
Bring the Unsealed Chest to Darion, who will open it and allow you to deliver the contents to their respective owners. Sylvanas' Music Box is one of the rewards from this chest, alongside 
Reins of the Crimson Deathcharger, 
Muradin's Favor, 
Jaina's Locket, and 
Tabard of the Lightbringer.
Trade or Buy It
Since Sylvanas' Music Box is Binds When Used rather than Bind on Pickup, it can be traded or purchased from other players on the Auction House if you do not wish to complete the questline yourself.
Tips
When used, the music box plays Lament of the Highborne — the same song as
Lament of the Highborne found in the Ghostlands. The Thalassian lyrics translate to a lament for the Sin'dorei, the Children of the Blood.See the video guide for a full walkthrough of the Shadowmourne questline and the Unsealed Chest rewards.
