Massena LAB · Uni-Racer

Strap for Massena LAB Uni-Racer UR

Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width20 mm
Case diameter39 mm
ReferenceUR
FamilyUni-Racer
MovementSellita caliber SW510 M BH b Hours, Minutes, Small Seconds | Chronograph

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the Uni-Racer UR

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Uni-Racer UR, seen from the bench

The Uni-Racer from Massena LAB features a 39mm stainless steel case with 20mm lugs. It is powered by the Sellita SW510 M BH b caliber with hours, minutes, small seconds, and chronograph functions. The movement offers the essential complications for a compact sporting chronograph.

Frequently asked questions

What is the lug width of the Massena LAB Uni-Racer UR?

The lug width of the Massena LAB Uni-Racer UR is 20mm. This measurement is proportionate to the 39mm case and allows a broad selection of compatible straps. To verify correct measurement, measure from the inner wall of the left lug to the inner wall of the right lug in a straight line perpendicular to the case tube.

Which strap do you recommend for the Massena LAB Uni-Racer UR?

For the vintage-racing character of the UR, we recommend a Rally in Cognac Brown with vegetable tanning: the colour pairs naturally with the ivory dial and narrates automotive heritage. Alternatively, a black alligator for a formal vision, or a dark grey NATO for tactile versatility.

How do I change the strap on the Massena LAB Uni-Racer UR?

Remove the spring bars (small pins holding the strap to the lugs) using a dedicated lever tool or a thin needle. Push slightly towards the centre of the case to release the spring, extract the old strap and insert the new one by aligning the holes. Verify that the spring bars are securely fastened and that the strap moves slightly (not rigidly).

Are aftermarket straps compatible with the Massena LAB Uni-Racer UR?

Yes, any strap with a 20mm lug width is compatible with the UR. We recommend checking strap thickness (typically 2.5–4mm for leather): excessively rigid straps may not insert smoothly into the lugs, whilst thin straps could create excessive play.

How long does a leather strap last on the Massena LAB Uni-Racer UR?

Durability depends on frequency of use, climate and tanning method. A vegetable-tanned strap resists 18–36 months with daily wear, accelerating in humid climates or if exposed to perspiration and water. Natural patina develops character over time. A premium alligator strap lasts longer (36–48 months). We recommend rotating with other straps and occasional maintenance with neutral balm.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only