The rarity of The Pirate's Booty Set is Rare, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
The Pirate's Booty Set is a skin for Tidehunter. The skin was added to the game on Invalid Date, it was created by Sparkwire.
The Pirate's Booty Set is currently one of the most popular skins, but it is rarely seen in the game due to its high price.