Formex model

Formex Reef: history, models and official videos

The Formex Reef is the Swiss brand's 300-meter diver's watch, available as the 42 mm Reef, the Reef GMT and the smaller 39.5 mm version. This page explains the three lines, the interchangeable bezel and what affects the value of a used Reef, and shows the official Formex videos.

Introduced: 2020 (Reef 42 mm)
Case: 42 mm, 39.5 mm
Movement: Sellita SW300 / SW330-2 / SW300-1, COSC
Water resistance: 300 m

A Watch 2 Million Years In the Making! Formex Blue Coral Reef – official video by Formex on YouTube

Where the Formex Reef comes from

Formex is a Swiss watchmaker that Monochrome describes as founded in 1999, known for sturdy, reasonably priced tool watches. The Reef, introduced in late 2020, was its first modern diver's watch and builds on the Formex Essence collection. The name was chosen through a promotion with the aBlogtoWatch community. At launch the Reef was a 42 mm steel diver with a COSC-certified Sellita SW300 automatic, water resistance to 300 meters and a sapphire crystal with anti-reflective coating.

The Reef family: 42 mm, GMT and 39.5 mm

The Reef has grown from one watch into a small family. The table lists the three main lines as they were launched.

Series	Years	References	Case	Movement
Reef 42 mm	2020	Reef Automatic Chronometer 300M	42 mm, 11.4 mm thick, 47 mm lug to lug	Sellita SW300, COSC, 42-hour power reserve
Reef GMT	2022	Reef GMT Automatic Chronometer 300M	42 mm, 11.4 mm thick, 47 mm lug to lug	Sellita SW330-2, COSC, caller GMT, 56-hour power reserve
Reef 39.5 mm	2023	Reef 39.5mm Automatic Chronometer 300M	39.5 mm, 11 mm thick, 45.5 mm lug to lug	Sellita SW300-1, COSC, 56-hour power reserve

All three share the same idea: a diver's watch with a chronometer-certified movement and 300 meters of water resistance at a price well below the big-name Swiss divers. Formex has also released special editions and colors on top of these lines, so a Reef you find may not match the standard configurations described here.

Interchangeable bezel and customization

The feature most owners mention is the bezel. On the Reef GMT and the 39.5 mm model the bezel can be swapped without tools, and Formex sells extra inserts in steel or zirconium oxide ceramic. The GMT can take either a 24-hour bezel or a 120-click dive bezel. Straps and bracelets also change quickly: the Reef uses quick-release spring bars, and Formex sells rubber, leather, NATO and steel bracelet options. Formex's own YouTube channel shows how to change the bezel on the Reef and Reef GMT.

The GMT is a caller (office) GMT. You set the 24-hour hand independently in one-hour steps by pulling the crown to the second position, which makes it easy to follow a second time zone without disturbing the local time.

What is a Formex Reef worth?

The Reef is a modern watch from an independent microbrand, and we are not aware of any documented auction results for it, so we do not quote any. Original prices give a starting point: the 42 mm Reef was announced at $1,670 on rubber and $1,790 on the steel bracelet, the Reef GMT at $1,800 to $2,250 depending on strap or bracelet, and the 39.5 mm Reef at 1,630 to 1,960 euros. Like most new watches, they typically sell for less on the pre-owned market than they cost new.

What affects the price of a used Reef: which model and size it is, the dial and bezel color, whether it still has the box, papers and COSC certificate, the condition of the case and crystal, and which straps, bracelet and spare bezels come with it. Complete sets with extra bezels are easier to sell than a watch on its own.

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Official Formex Reef videos

The videos come from the official Formex YouTube channel and cover the Reef, the Reef GMT and the 39.5 mm version, new straps and bezel options – the guide to changing the bezel is How To Easily Change The Bezel On Your Formex Watch - Formex Reef or Formex Reef GMT.

More Formex videos, sorted by model: all official Formex playlists.

Sources (5)

SwissWatchExperts is not affiliated with Formex. Brand and model names are trademarks of their owners; the videos are embedded from the official Formex YouTube channel.

← Formex: history, models and value

Frequently asked questions

When was the Formex Reef introduced?

The first Reef, a 42 mm diver, was presented in October 2020 with shipping planned for December 2020. The Reef GMT followed in 2022 and the 39.5 mm Reef in December 2023.

How big is a Formex Reef?

The Reef and Reef GMT are 42 mm wide, 11.4 mm thick and 47 mm lug to lug. The smaller 39.5 mm Reef is 11 mm thick and 45.5 mm lug to lug.

Which movement is inside a Formex Reef?

The 42 mm Reef uses a COSC-certified Sellita SW300, the Reef GMT a COSC-certified Sellita SW330-2 and the 39.5 mm Reef a COSC-certified Sellita SW300-1.

Can you change the bezel on a Formex Reef?

Yes. On the Reef GMT and the 39.5 mm Reef the bezel swaps without tools, and Formex sells extra steel and ceramic inserts. The GMT can take a 24-hour bezel or a dive bezel.

How water resistant is a Formex Reef?

All Reef models are rated to 300 meters.

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