Introducing a new Shall Star with a rarely seen dive feature in a timepiece that is equally technical, durable and stylish.


The iconic Shell Star collection is symbolic of Delma’s dive watch expertise. Over the 45 years since it was first released it has showcased an evolution of form, materials and functionality. The new Shell Star Decompression Timer introduces a new iteration of sophisticated diving technology built upon the collections’ cherished design.

The functionality of the Shell Star Decompression Timer is based on research of the 1950s and 60s by Swiss dive pioneers Hannes Keller and Albert Bühlmann. Both former students at the University of Zurich, their combined expertise in mathematics, physics and diving motivated them to perform revolutionary research in the diving field. They recognized the impact of altitude on decompression and developed tables with specific gas mixtures for different elevations. Bühlmann focused on identifying the correct combination of gases while Keller performed experimental dives to test their theories. The resulting tables enabled safe decent at sea level and in mountainous terrain and were even adopted by the Swiss military in 1972. Still today considered to be the most intuitive of their kind, they uniquely take into account the need for multiple decompression stops for deeper and longer dives.

How it works

The Delma Shell Star Decompression Timer is optimized for diving with air breathing at 0-700 meters above sea level. The diver uses the unidirectional bezel to time his dive. The vertical scale on the dial at 12 o‘clock corresponds to their dive depth in meters or feet. It enables the diver to clearly see if their dive is within the no-decompression limit (NDL) where no decompression is required or whether decompression stops are necessary. The NDL time is reflected by the white markings on the rings, while the amount of decompression stops and their duration are shown by the numbers.

“The Shell Star holds a special place for DELMA as the brand’s first professional divers’ watch. Since the release of the first edition in 1975, the series has evolved technically and visually. With the new Shell Star Decompression Timer we showcase our expertise in diving with a new function rarely seen in mechanical timepieces.”


Unlike other comparable timepieces, DELMA’s Shell Star Decompression Timer utilizes Keller and Bühlmann’s research to clearly display when multiple decompression stops are needed for dives at sea level and beyond. In keeping with its technical diving functionality, the Decompression Timer features a helium escape valve and a water resistance to 500 m / 1650 ft. It is offered with a black, blue or orange unidirectional bezel with either a stainless steel bracelet or rubber strap.

All models are automatic and contain a SW200 movement with date and DELMA customized rotor. Key historical characteristics include a spade central seconds hand, the railway track and orange and white indexes. The stainless steel case is sealed with a transparent case back revealing the intricate movement.

Durability and strength have always been essential to the Shell Star and this new release is faithful to the collection. The bold decompression timer functionality completes a unique diving tool worthy of attention.

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