MB&F unveils the dazzling new LM Perpetual Chromatic Editions

• The brand’s award-winning perpetual calendar is presented with gem set bezels. • 18K white gold version with blue sapphires. • 18K white gold version with purple sapphires. • 18K red gold version with red rubies.

Kunaal Khemka

May 26, 2026

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What is the MB&F LM Perpetual Chromatic Editions?

They are gem set versions of MB&F’s iconic LM Perpetual. The three editions include an 18K white gold version with a bezel set with 48 baguette-cut blue sapphires (1.95 carats) from either Madagascar or Sri Lanka, an 18K white gold version with a bezel set with 48 baguette-cut purple sapphires (1.93 carats) from Madagascar and an 18K red gold version with 48 baguette-cut red rubies (1.95 carats) from Mozambique. Each edition is limited to 8 pieces each.

What makes the LM Perpetual so unique?

MB&F LM Perpetual Chromatic Blue. — Image: LM Perpetual Chromatic Blue with 48 baguette-cut blue sapphires from either Madagascar or Sri Lanka. Notice the PVD-treated blue hands that match the blue sapphires. Notice the two large mainspring barrels on the caseback. Movement finishing is according to *“19^th century style; internal bevel angles highlighting hand craft; polished bevels; Geneva waves; handmade engravings.”*

Introduced in 2015, the LM Perpetual’s movement or “engine” (MB&F speak) is the creation of Stephen McDonnel. Hailing from Northern Ireland, he studied Theology at Oxford University and watchmaking at WOSTEP in Neuchâtel, Switzerland. He is one of the original “F” or “Friends” of the brand, and among the first few watchmakers who assembled the movements for the Horological Machine N°1. He rethought the “entire mechanical basis” of the perpetual calendar complication. Historically perpetual calendars have used 31 days as a default, and then decide whether the months have 30 days, or 28 or 29 days in the case of February and Leap Year. The LM Perpetual’s movement uses 28 days as a default and then “adds” days depending on the respective months.

Also Read: MB&F introduces the phenomenal new LM Sequential Flyback EVO

Are the LM Perpetual Chromatic Editions powered by a manual winding movement?

MB&F LM Perpetual Chromatic Red. — Image: LM Perpetual Chromatic Red with 48-baguette red rubies from Mozambique. Notice the 5N PVD-treated hands that match the red gold case. Notice the large 14 mm balance wheel in the centre. The LM Perpetual’s case comprises of 69 parts.

Yes. They are powered by the “fully integrated perpetual calendar developed for MB&F by Stephen McDonnell, featuring dial-side complication and mechanical processor system architecture with inbuilt safety mechanism.” It comprises of 581 parts and 41 jewels, beats at a luxurious rate of 2.5 Hz or 18,000 vph and has a power reserve of 72 hours or 3 days delivered from double mainspring barrels.

“The mechanical processor also enables an inbuilt safety feature that disconnects the quickset pushers during the date changeover, eliminating any risk of damage while the date is changing.”

What are the dial features?

MB&F LM Perpetual Chromatic Purple. — Image: LM Perpetual Chromatic Purple with 48 baguette-cut purple sapphires from Madagascar. Notice the PVD-treated purple hands that match the purple sapphires.

Open dial showcasing much of the LM Perpetual’s engine, with the centerpiece being the large (14 mm) bespoke variable-inertia or free-sprung balance wheel with four regulating screws. Hours and minutes are displayed on a subdial at 12 o’clock; day of the week on a skeletonised subdial at 3 o’clock; date on a skeletonised subdial at 9 ‘clock; month on a skeletonised subdial at 6 o’clock; retrograde leap year indicator between 7 and 8 o’clock and retrograde power reserve indicator between 4 and 5 o’clock.

What are the three versions’ case features?

The case is crafted from either 18K white gold (blue sapphires and purple sapphires versions) and 18K 5N+ red gold (red rubies version). They measure 44 mm (diameter) * 17.5 mm (thickness). Dial side and caseback feature a sapphire crystal, coated with anti-reflective material on both sides. Water resistant up to 30 metres / 90 feet / 3 ATM.

The two 18K white gold versions come with a hand-stitched white alligator leather strap and the 18K red gold version with a hand-stitched brown alligator leather strap. They are fitted with a case matching folding buckle.

What do we think?

Like tourbillons, perpetual calendars are a dime and dozen. Often there is little to differentiate them across brands. Few brands genuinely offer one that is original in execution. A. Lange & Söhne’s Lange 1 Perpetual Calendar and Patek Philippe’s Reference 5236 In-Line Perpetual Calendar are notable examples.

MB&F’s LM Perpetual, with its 28-days default programming instead of the standard 31-days, in addition to its inbuilt safety feature, puts it among the most advanced and thoughtful perpetual calendars in design and execution in the world. It won the Calendar Watch Prize at the Grand Prix d’Horlogerie de Genève awards ceremony in 2016.

The LM Perpetual Chromatic Editions add a pop of colour and bling to this horological icon, marrying the best of independent watchmaking with the best of gem setting. With only 8 pieces produced for each version, they are extremely rare. The 24 fortunate collectors who get their hands on them will be able to cherish them for decades to come.