Strap for Seamaster Aqua Terra 150M Co-Axial 38.5 Stainless Steel / Diamond / Black / Bracelet

The lug width is 20 millimetres. This measurement represents the distance between the two metal attachment points (bars) that connect the strap to the case. It is a construction specification by Omega for this reference and determines the compatibility of any aftermarket strap.

Black or dark brown alligator is the optimal choice, as it reflects the minimalist aesthetic code of the Aqua Terra. Shell cordovan represents a premium alternative for durability and ageing patina. Calf leather tinted in cognac or mid-brown tones creates a refined yet less formal pairing. Avoid rubber and canvas, which are too casual for the identity of this model.

Position the watch on a soft surface with the dial facing downward. Locate the horizontal spring bars that secure the strap to the lugs. Using a flat tool (spring bar tool), gently press the spring bar from the outside toward the centre to disengage it, then remove the old strap. Insert the new strap by aligning the holes with the spring bars and snap the bar into position. Verify that both sides are perfectly secured.

Any strap constructed with a 20 millimetre lug width is compatible, provided the construction respects Omega tolerances (±0.2mm). Avoid generic straps that claim approximate compatibility. Bespoke artisanal straps guarantee perfect fit without vertical play and allow you to choose leather, colour, and stitching thread according to your aesthetic preferences.

Durability varies based on material, usage, and maintenance. Alligator and shell cordovan maintain structural integrity for 5–8 years of daily wear. Vegetable-tanned calf typically lasts 3–4 years. Exposure to sweat, moisture, and extreme temperatures accelerates wear. A well-maintained strap (dried after water exposure, stored in a temperature-controlled environment) ages with elegant patina. The 18-month warranty from Casati Milano covers manufacturing defects.