Audemars Piguet isn't only about Royal Oaks. The tonneau case is 25mm and 30mm long making it larger than a classic Cartier Tank. The case features a hidden strap system for the lugs. It has the original signed strap and buckle too. The dial is a really nice cut of Tiger Eye Stone with the small AP branding. The dial shows no cracking or marks. The reference 5391 is a rare model to find, especially with the stone dial. It's not often that vintage Audemars Piguet blows us away at this price point so handling a watch like this is very special.
Stone dials from other brands have appreciated heavily, but they have also become a saturated market. Vintage stone dials from the Holy Trinity (Patek, Audemars, and Vacheron) have always been hard to come by, and that won't change anytime soon.