Strap for Seiko Prospex Divers Marinemaster 300 Ninja Tuna

The lug width of the Seiko Prospex Divers SBBN035 is 22 mm (measured shoulder-to-shoulder between the lugs). This dimension is critical to ensure a perfect fit without vertical play. To verify, use a calliper positioned directly in the space between the case lugs, or consult Seiko's technical documentation. A strap with a different width would cause instability and potential premature wear to the keepers.

For the SBBN035, we recommend alligator straps in dark brown or black for elegance and aquatic durability, or rubber for maximum resistance to marine environments. If you desire versatility, a NATO strap in synthetic material guarantees practicality and easy changes. Vegetable-tanned calf leather at least 1.4 mm thick is an intermediate choice combining aesthetics and functionality.

To change the strap, remove the spring bars from the lugs using an appropriate tool (plastic or dedicated steel lever). Gently push one end of the spring bar inward until the spring retracts, then pull the bar out of the first lug. Repeat on the other side. Insert the spring bar through the holes in the new strap and position the strap in the first lug, then press until the bar clicks. Repeat on the other lug, verifying alignment.

Yes, provided the strap has a 22 mm lug width. Any quality strap (leather, rubber, NATO) with this width is compatible. We recommend also verifying the total length of the strap to ensure proper fit on your wrist. Milano Straps' handcrafted straps are available in this size and customisable according to your preferences.

A quality leather strap (alligator or vegetable-tanned calf) typically lasts 3–5 years with regular use, depending on moisture exposure and care. Since the SBBN035 is a diving watch, if you use it frequently in water, it is advisable to alternate with rubber or NATO straps to extend the leather's lifespan. Proper drying and occasional protective wax treatments significantly extend durability.