Strap for Mission Timer UX SDR EZM 2B

The Sinn Diving Watches 403.050 features a lug width of exactly 22 millimetres. This measurement is taken by positioning a digital calliper between the two horizontal lugs of the case at their narrowest point. A lug width of 22mm is proportionate to the 44mm case diameter and ensures compatibility with a vast range of aftermarket straps, including the bespoke leather straps offered by Milano Straps.

The choice of strap depends on intended use. For frequent professional diving, a vulcanised rubber or composite synthetic strap is ideal, as it resists chlorine, saltwater and ultraviolet exposure. For mixed professional and formal wear, a vegetable-tanned calf leather strap offers lasting elegance and develops a beautiful patina over time. For those seeking authentic military aesthetic, a premium NATO strap in technical black textile maintains the Germanic minimalism of the 403.050. All these materials are available in 22mm width at Milano Straps.

Changing the strap requires only a few steps: 1) obtain a spring bar tool, 2) place the watch on a soft surface, 3) insert the flat tip of the spring bar tool into one of the small holes at the side of the lug, apply gentle pressure inward to compress the spring, 4) withdraw the metal bar together with the old strap, 5) insert the new lug end under the lug and secure the bar in the opposite position. The operation demands care to avoid scratching the case. Milano Straps provides detailed video tutorials for this procedure.

Yes, any strap with a lug width of 22mm is compatible with the 403.050. Quality aftermarket straps equivalent to original equipment do not damage the watch and offer greater aesthetic variety and specialised materials. Milano Straps offers straps in leather, NATO textile, rubber and technical materials, all certified for 22mm fitment and crafted to Italian artisanal standards.

A quality leather strap (alligator, calf, or shell cordovan) in daily use has an average lifespan of 3–5 years before replacement is required. Vegetable-tanned calf straps tend to last longer and age beautifully, developing patina and character. Frequent exposure to moisture, saltwater and chlorine shortens leather lifespan. For regular water immersion, alternating leather straps with rubber or NATO models is advisable. Proper drying and occasional conditioning with natural leather balms can substantially extend strap life.