Haffenreffer Private Stock  (commonly referred to as P-Stock, The Green Death, Heffy's, Haffen-Wrecker or The Golden Cap) is a brand of malt liquor first brewed in 1953 at the Haffenreffer Brewery in Jamaica Plain, Boston. In 1965, production of the brand moved to Narragansett Brewing Company in Rhode Island and then to the Falstaff Brewing Company. It was brewed in Latrobe, Pennsylvania and Utica, New York under license from Haffenreffer & Co. 
Private Stock was discontinued in 2013.
The song Juicy by the rapper Notorious B.I.G. mentions Private Stock in the lyrics. The song Old School by the rapper Tupac mentions Private Stock in the lyric, "You diggy don't stop, sippin on that Private Stock".