Nautiko & Seikonaut

Two families share this page. The Nautiko takes the rounded-octagon case and horizontally embossed dial of the Nautilus; the Seikonaut follows the sportier Aquanaut line with its moulded rubber-style strap. Both are 41mm, both use sapphire glass with anti-reflective treatment, and most carry the Seiko NH35 automatic. Open-heart builds run the NH38 so the balance wheel stays visible through a cut-away dial.