According to our good friends at Wikipedia, A'bunadh is a cask-strength single malt whisky from the Aberlour Distillery in Scotland. Though it has no age statement, it is released in limited run batches, each batch carrying a unique number on its label. Each batch of this whisky is blended from barrels ranging from 5 to 25 years old.
Rumour has it that when the second pair of stills were put in in 1975, a time capsule was discovered behind the name plate, containing an 1898 newspaper about the distillery fire wrapped around an 1898 bottle of Aberlour. The workmen who discovered the bottle polished off four fifths of the bottle during their lunch break, but the remains of the bottle went off to the laboratories in Keith, and were analysed. A'bunadh is an attempt to recreate this single malt.
The word a'bunadh is roughly translated into English from Scottish Gaelic as "original."
Batch 15 is from 2005 and bottled at 59.6%. It's widely considered to be one of the best bottlings.