The Vintage Hewlett Packard HP 42S RPN Scientific Calculator is a rare find for collectors and enthusiasts of vintage electronics. Made in Singapore, this HP calculator features a classic RPN (Reverse Polish Notation) interface and is in fully functional condition. The calculator comes in its original open box packaging, adding to its charm and authenticity as a piece of consumer electronics history. With the renowned HP brand and model being the 42S, this calculator is a valuable addition to any vintage calculator collection.