A rare piece of history from Apple Inc.’s storied early days in Silicon Valley will go to the highest bidder.

Steve Jobs’s Apple-1 Computer prototype is being auctioned by Boston-based RR Auction, with current bids at $278,005. Bidding ends on August 18. RR Auction sold the Apple-1 computer in September 2018 for $375,000.

The prototype, which was considered “lost until recently,” is what the Apple co-founder used to demonstrate the Apple-1 to personal computer store owner Paul Terrell in 1976.

According to the item description on RR Auction’s website, Jobs and co-founder Steve Wozniak originally envisioned the Apple-1 computer as part of a $40 do-it-yourself kit.

Terrell convinced the entrepreneurs to turn the product into a pre-assembled personal computer for $666.66 and gave them their first big order.

“There is no Apple-1 without this board— it’s the holy grail of Steve Jobs and Apple memorabilia,” said Bobby Livingston, executive vice president at RR Auction.

The device passed through Wozniak’s hands, too: The prototype appears to have been hand-soldered by Wozniak on a unique “Apple Computer A circuit board,” according to auction house description. The prototype shows Wozniak’s unusual “three-handed technique using a wire in one hand, soldering iron in the older and solder with his mouth.”

In 1976, Terrell took Polaroid photos of the prototype, which were matched to the circuit board. The prototype was examined and authenticated in 2022 by Apple-1 expert Corey Cohen, who also wrote an accompanying 13-page report.