Up for sale today is a unique and uncommon Seiko diver, the Marinemaster Tuna reference SBBN031, the last of the Marinemaster branded Tuna watches before the switch to full Prospex branding. This watch comes in at 47.5mm in diameter, but don't let that put you off, since the lug to lug is only 44.5mm, it wears much better than the diameter would suggest. The thickness comes in at 14.7mm, but some of that is due to the double domed crystal. The case and original bracelet show some signs of use and scratches, but are in very good condition overall. The bracelet comes with full links for a 20cm+ fit and is currently sized for an 18cm wrist. The watch is powered by the 7C46 high torque quartz movement with an anti backlash mechanism for the seconds hand like the Grand Seiko 9F series movements. The watch is a rare, late production example having been made in 2020. The movement runs perfectly and there are no issues to report. Included with the watch are the original inner box, papers, manual, hang tag, and extra bracelet links. I'm looking to get $850 including shipping within the USA for this piece. This makes it the cheapest in the country currently. For international shipping, feel free to send a message for a quote. Multiple payment options are accepted, and again, feel free to reach out if you have any questions.