904L is a high grade stainless steel prized for its corrosion resistance and high polish; Grade 5 titanium is a lightweight, high strength alloy prized for comfort and durability. Most watches use one or the other. The Meridion VX01-E uses both, a 904L steel case paired with a Grade 5 titanium case back, and the reasoning behind that combination says a fair amount about how case materials actually work.

What Is 904L Stainless Steel?

904L is a high grade austenitic stainless steel alloy, distinguished from more common 316L “surgical” steel by higher levels of chromium, nickel, molybdenum, and copper. That extra alloying content is what does the work: it gives 904L noticeably stronger resistance to pitting and corrosion, particularly in chloride rich environments like seawater, and lets the metal take a brighter, more reflective polish than 316L typically achieves.

904L isn't a marketing term; it's a specific, higher cost alloy that takes real machining effort to work with, which is exactly why it remains less common than 316L across the watch industry generally, even though its corrosion resistance is measurably better.

The numbers themselves come from established metallurgical grading systems (UNS and EN standards, among others), the same classification framework used for stainless steel across aerospace, marine, and medical equipment. Watchmaking didn't invent these grades; it borrowed proven industrial alloys and put them to a much smaller, more visible use.

What Is Grade 5 Titanium?

Titanium used in watchmaking comes in different grades, and the distinction matters more than the word “titanium” alone suggests. Grade 2 titanium is commercially pure, with no significant alloying elements; it's soft enough to machine easily but correspondingly more prone to surface scratches. Grade 5 titanium, also known as Ti6Al4V, is alloyed with aluminum and vanadium, which dramatically increases its hardness and structural strength, closer to stainless steel, while it remains substantially lighter than steel.

Titanium of any grade is also naturally hypoallergenic: it forms a stable, inert oxide layer on its surface and contains no nickel, which is the metal most commonly responsible for skin sensitivities and contact allergies in jewelry and watch cases.

904L vs. Titanium: Which Is Better for a Watch Case?

“Better” depends on what you're optimizing for. 904L wins on corrosion resistance and polish; Grade 5 titanium wins on weight and, for anyone with metal sensitivities, on comfort against the skin.

Why Combine Both in One Case?

Rather than treating the choice as either/or, combining both materials in one case lets independent watchmakers put each material where its strengths actually matter. The visible case, the part that catches light and defines the watch's presence on the wrist, benefits from 904L's higher polish and corrosion resistance. The case back, which sits directly against the skin all day, benefits from titanium's lighter weight and hypoallergenic surface. It's a deliberate engineering decision, not a compromise driven by cost: each material does the job it's genuinely best suited for.

It's also, notably, not a cheap way out. Machining both a 904L case, which is hard to work, and a Grade 5 titanium back, which is equally demanding, into the same watch costs more in tooling and labor than standardizing on a single material throughout. That's worth knowing when a watch in this price range discloses both materials rather than quietly using the easier, cheaper option for the parts a buyer is less likely to inspect closely.

Inside the Meridion VX01-E :

This is precisely the logic behind the Meridion's construction. The case measures 41.4mm in diameter and 12.2mm thick, with a 45.5mm lug to lug, a ten sided, brushed and polished 904L stainless steel case, chosen for its corrosion resistance and the brighter finish it can take. The case back is a screwed Grade 5 titanium piece featuring dual smoked sapphire windows onto the movement, keeping the surface that sits against the wrist lighter and hypoallergenic. Water resistance is rated to 120 meters.

VOXEL extends the same 904L steel into the integrated bracelet option, alongside an Alcantara textile strap available in six colors, across a limited first edition in three dial variants: Charcoal Grey, Electric Blue, and Silver Star. Pricing is €2,500 on the Alcantara strap and €2,850 on the integrated steel bracelet, excluding VAT, with pre-orders opening October 1, 2026.