Delma Shell Star Decompression Timer

The family-owned, independent Swiss watch brand Delma revives their iconic Shell Star collection by presenting a new diving watch with the Decompression Timer.

Delma’s professional diving watch Shell Star was introduced in 1975. The newly released Shell Star Decompression Timer is a technical, durable and stylish deep diver.

Delma Shell Star Decompression Timer

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.

Delma Shell Star Decompression Timer

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.

Delma Shell Star Decompression Timer

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.

Delma Shell Star Decompression Timer

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. Dressed in a robust 44mm diameter case and water resistant to 500 meters (1650 ft), this automatic diving timepiece also features a helium escape valve.

Delma Shell Star Decompression Timer

The  Shell Star Decompression Timer watch is offered with a black, blue or orange unidirectional bezel with either a stainless steel bracelet or rubber strap.

Delma Shell Star Decompression Timer

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.

Technical details

Model: Shell Star Decompression Timer

Material: Stainless steel
44 mm diameter
13.8 mm thick case
Helium escape valve at 9 o’clock
Unidirectional bezel in black, blue or orange anodized aluminum
Water resistant to 500m / 1650 ft

Black or blue dial with decompression timer
Luminescent indexes and hands

Stainless steel bracelet with deployant clasp with pushers or genuine rubber strap with stainless steel buckle

SW200 automatic movement
Self-winding mechanism with ball bearing, frequency 28’800, 26 jewels, power reserve of 38 hours
Central hour, minute, seconds hands and date at 3 o’clock

Blue Delma designed leather box

Retail price
With Stainless steel bracelet: CHF 1150 / EUR 1250 / USD 1350
With Rubber strap: CHF 1100 / EUR 1200 / USD 1290