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MB&F · Horological Machines

Strap for Horological Machine N°3 HM3 Chocolate Frog

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

Lug width

20mm
20 mm strapsAll MB&F
Lug width20 mm
Case diameter47 mm
Reference31.TL.TP
FamilyHorological Machines
MovementMB&F caliber HM3 Hours, Minutes, Day / Night Indication | Date | Power Reserve Indicator
CaseTitanium

Spring bar

Swiss Standard universal spring bars

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

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Straps for the Horological Machines 31.TL.TP

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Horological Machines 31.TL.TP, seen from the bench

The MB&F Horological Machine No.3 "Frog" (reference 31.TL.TP) features a 47mm titanium case housing the proprietary HM3 caliber with dual 20° inclined tourbillons visible through domed sapphire crystals. This unconventional timepiece displays hours, minutes, day/night indication, date, and power reserve while combining mechanical architecture with distinctive three-dimensional design. The 20mm lug width is determined by the case geometry and titanium construction provides a natural grey-metallic finish contrasting with matte black case details.

Frequently asked questions

What is the exact lug width of the MB&F Horological Machines 31.TL.TP?

The lug width of the MB&F Horological Machines 31.TL.TP is precisely 20mm. This measurement represents the distance between the inner lugs of the case where the strap attaches. It is essential to verify this dimension before purchasing an aftermarket strap to ensure complete compatibility and avoid lateral play or installation difficulties.

Which strap material is most suitable for the 31.TL.TP?

The choice depends on usage and aesthetic preferences. Alligator leather is the most refined option for formal contexts, emphasizing the luxury nature of the timepiece. Vegetable-tanned calf leather offers understated elegance and natural patination over time. NATO straps provide versatility and practicality for sporty wear. Premium FKM rubber is ideal for humid environments or those who value secure grip and minimal maintenance. Each material conveys a different approach to owning the watch.

How do you change the strap on the MB&F Horological Machines 31.TL.TP?

The 31.TL.TP employs bayonet lugs. Position the watch on a stable surface with the case facing away. Gently push the strap towards the inside of the case to release the retention mechanism, then extract the strap from the lug. To install a new strap, align the strap width with the lugs and press until you hear the click of engagement. Milano Straps provides detailed guides and support for this procedure.

Are aftermarket straps compatible with the 31.TL.TP?

Yes, provided they respect the 20mm lug width and the specific bayonet lug geometry of the model. Milano Straps offers a comprehensive collection of 20mm straps tested and compatible with the 31.TL.TP, from classic leather options to modern NATO and rubber variants. All available straps are ready for shipment and customizable according to customer preferences.

How long does a leather strap last on a watch like the 31.TL.TP?

The longevity of a leather strap depends on material quality, frequency of use, and environmental conditions. A high-quality alligator or vegetable-tanned calf strap can last 3-5 years with moderate daily use. Exposure to excessive moisture, sweat, and UV rays accelerates aging. To extend strap lifespan, alternate use with other models, protect from direct impacts, and for premium leathers, apply periodic conditioning treatments.

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