Type 5

The Type 5 takes Ressence's oil-filled display concept and waterproofs it to 300 meters, which sounds straightforward until you consider what that actually requires. The ROCS 5 module is pressurized with oil, and getting that system to survive depth meant engineering a pressure-compensation valve that equalizes internal and external pressure as you descend. No other watch on the market works quite like it.

What it is

Ressence launched the Type 5 in 2015 as a direct response to enthusiasts asking whether the oil-filled Type 3 could be taken diving. The answer was yes, but it required a complete rethink of the case architecture. Benoit Mintiens, the Belgian designer behind the brand, had to solve the problem of a sealed, oil-filled module inside a case that also needed to flex with external water pressure.

The solution is a flexible membrane and compensation valve that keeps the internal oil pressure matched to ambient pressure at depth. It remains the most technically demanding reference Ressence has made.

Buying notes

The oil in the ROCS 5 module is the whole watch, and it ages. Yellowing over years is well-documented on older examples; inspect the dial carefully and ask for photos in natural light before buying secondhand. The compensation valve is a proprietary Ressence system and cannot be serviced by anyone outside the brand's authorized network.

Battery replacement (the e-Crown variant) and any oil-related service must go back to Ressence directly, which means long turnarounds and costs that surprise buyers used to mainstream service pricing. The 46mm case is genuinely large; wrist time before buying is strongly recommended.

Market read

The Type 5 trades in a thin secondary market. Prices have held reasonably well given the low production volumes, but liquidity is slow compared to Rolex or even other independent brands with broader collector bases. Expect to wait for the right buyer at full price.

The more recent e-Crown versions command a premium over early mechanical-crown examples.

Service expectations

The base movement is an ETA 2824-2, but service cannot be treated like a standard ETA job. The ROCS 5 oil-filled module requires factory-level disassembly and re-sealing with the correct fluid, and only Ressence's own service center has the tooling and oil specification to do it correctly. Budget accordingly and plan for a multi-month service interval.