The product is a rare billon tanka coin from the Delhi Sultanate period of Firuz Shah Tughluq, who reigned from AH 752 to 790 (1351-1388 AD). This coin was minted in India and belongs to the historical period of independent kingdoms. The composition of the coin is billon, which is a type of currency made of a combination of metals like silver and copper. This rare coin provides a glimpse into the history and minting practices of the Delhi Sultanate during the rule of Firuz Shah Tughluq.