Seiko Tuna, as watch enthusiasts call it because of its circular case, is a professional dive watch that runs in calibre 7C46. The well-appreciated unique case acts as a shield; it is securely screwed for protection, matched by Seiko’s proprietary impact resistant Hardlex Crystal. Seiko Tuna is a very accurate and reliable watch with battery that can last for up to 5 years. Other entry level tuna divers watches are commonly called Seiko Baby Tuna.
It is definitely something to brag about to divers and watch collectors alike. A unique piece that set the standards in professional divers watches.