Strap for Seamaster 300 Master Chronometer Stainless Steel / Blue / Bracelet

The lug width of this reference is precisely 21.00 millimeters, measured from the inner shoulder of the case at the 12 o'clock position to the corresponding shoulder at the 6 o'clock position. This measurement is not a common commercial standard; always verify by measuring your watch directly before ordering a strap.

Dark tan vegetable-tanned alligator and medium brown calf offer the most natural aesthetic contrast with the black dial. For frequent underwater use, a dense cotton NATO or vulcanized rubber strap preserves functionality without compromising the elegance of the case.

Remove the watch from your wrist and position it with the case facing upward. Use a spring bar tool to apply gentle inward pressure on one of the pins, creating sufficient space to extract the strap end. Repeat the operation from the opposite side. Installation of the new strap follows the reverse procedure: insert the pins into the designated holes, ensuring they are perfectly centered and locked.

Yes, all straps with 21mm lug width are compatible. MilanoStraps offers a dedicated collection of 21mm straps in various materials (alligator, calf, shell cordovan) with customization options such as deployant clasp, embroidered initials, and choice of stitching thread.

A vegetable-tanned strap typically lasts 3-4 years with normal daily use; vegetable tanning is more resistant to salt water than industrial tanning. Shell cordovan reaches even 5-6 years thanks to structural density. Frequent exposure to salt water shortens durability; it is recommended to rinse the strap with fresh water after immersions and dry it completely. Rotating between two straps significantly extends the useful life of each.