Strap for Seamaster Diver 300M Automatic 41.5 Chronograph Stainless Steel / Blue / Bracelet

The lug width is 20mm. This width is Omega's standard for 41.5mm cases in the Seamaster Professional family. To verify it, measure the space between the inner edges of the lugs with a calliper: it must be exactly 20mm. Do not confuse the lug width with the case thickness; the lug is the cylinder that accommodates the strap.

It depends on usage: for formal elegance choose brown alligator with light ridge; for versatility and salt water resistance, Italian vegetable-tanned calf aged; for authentic diving functionality, professional textile NATO or silicone rubber; for balance between sports and refinement, ebony shell cordovan.

Remove the watch from your wrist. Use a spring bar tool (supplied with many straps) or a plastic tool to gently press inward on the sides of the lug, releasing the spring that holds it in position. The lug will detach from the case. Insert the new strap by aligning the holes with the lug and press until you hear the spring click back into place. Do not use hammers or metal tools as they will damage the case finish.

Original Omega straps are built to very tight tolerances and available in a limited range. Aftermarket straps, such as those handcrafted by Milano Straps, offer infinite choice of materials (alligator, calf, cordovan, textiles), aesthetic customization (coloured stitching, initials, textures) and functional adaptability, while maintaining comparable or superior construction quality. For intensive diving use, certain technical NAIOs even exceed Omega standards.

A high-quality leather strap (vegetable tanning, structured calf, cordovan) lasts 3-5 years with regular use, if properly maintained: air drying after water exposure, gentle cleaning with a soft brush, annual treatment with protective wax. Salt water accelerates wear; if you dive frequently, alternate with technical NATO or rubber. Milano Straps offers an 18-month guarantee and free stitching replacement in the first year.