The Sinn 157 EZM-4 Achilles – Redefining Chronograph Watch Design

When listing top countries in terms of their watchmaking expertise and tradition, very few would include Germany. Those who do are either avid fans with personal experience owning a German-made handwatch or they are genuine experts in horology. Or both, for that matter. Others are probably not aware that German watchmaking dates back to the early 16th century. A long-lived tradition that has been marked by engineering expertise, which comes as no surprise when German heritage is considered in general.

We've already touched base with Sinn watches, Germany's top brand, a while back, and this time our focus will be on one of their most renowned Chronographs, the Sinn 157 EZM-4. This is a truly special model, so stay tuned for an in-depth look at everything this unique timepiece has to offer.

The orange section of the special chronograph utility Sinn 157 EZM-4 Chronograph features is further spotlighted by a FKM Quick Release Rhombus Orange Rubber watch strap, not solely for aesthetic purposes.  Matching its orange shade perfectly additionally increases the readability of the dial.

There's something strange about Sinn 157 EZM-4

That's probably the first thing that goes through the mind of someone who sees the 157 EZM-4 Chronograph. Which is a natural reaction when someone sees a watch that features a left-hand crown placement for the first time. Destro watches, or "LHD" (Left-Hand Drive) watches, although rare, are not new on the market. They are primarily designed for left-handed owners. However, that's not the case with the 157 EZM-4. This Sinn Chronograph, like several of their other flagship models, also features a left-hand crown placement, despite being designed for right-handed wearers. Why is that the case, then?

Sinn 157 EZM-4 Chronograph day-date black Dial with a distinctive left-hand crown placement and paired with a complementary black Q.R. Pilot watch strap 20mm or 22mm Revive Watch Strap for elevated elegance

To paraphrase one of Sinn's marketing and communication executives, the models with the crown is positioned on the left, such as the 157 EZM-4, are designed to be worn on the left wrist, and the crown is unordinarily positioned to prevent injuries on the back of the hand during missions or any other strenuous or everyday activities. German engineering at its finest, with every practical detail taken into account for a specific model and circumstances. It's worth noting that Sinn has a long tradition of creating original models. For example, the Sinn 103 ST has been in production since the company's inception.

Talking about authentic features, EZM is a German abbreviation for a mission timer, indicating that Sinn watches belonging to this series are primarily designed as tool watches for specialized missions. It comes naturally, as Helmut Sinn, the founder of Sinn, was a World War II pilot and a flight instructor.  Namely, the EZM-4 is a specialized tool watch primarily designed with the needs of firefighters, doctors, and paramedics in mind. Nicknamed Achilles, it's dedicated to Prof. Ernst Achilles, head of the fire brigade in Sinn's hometown, Frankfurt Am Main. The 157 EZM-4 features authentic elements to cater to the specific needs of these three professions in their everyday fieldwork activities. Let's discuss them in detail.

Special Chronograph features of the Sinn 157 EZM-4

A single glance at the EZM-4 dial reveals that it features special enhancements. There are two chronograph activities incorporated to keep the firefighters and the people they are rescuing safer. The first one is a pulsometer, which is clearly indicated by the German phrase "Puls" (meaning pulse) and "Schlage" (meaning beat), printed at the left part of the outer ring of the dial. The user starts a chronograph pusher when they feel the pulse, counts a set number of beats (15 or 30), and then stops the chronograph. The number displayed by the chronograph's seconds hand on the pulsometer scale indicates the heart rate in beats per minute (BPM).

The second special chronograph feature of the EZM-4 is designed to accommodate the time limits for operating respiratory firefighting gear. Namely, the safe zone for using it during interventions is 15 minutes, which is marked by a green color. The following 15-minute limit is marked in red, indicating a potential danger of being at risk of a shortage of air and exposure to a hazardous surrounding atmosphere, such as vapor, toxic air, smoke, or dangerous particles.

The white tips of the hour, minute, and chronograph hands of the Sinn 157 EZM-4 Chronograph are ideally complemented by a White Large Holes Rally FKM Quick Release Rubber Watch Strap, creating an elegant yet casual combo that is great for everyday use.

Although packed with features, including the subdial and date complication alongside the described special chronograph feature, the EZM-4 dial provides excellent readability even in the most harsh conditions, ones that firefighters regularly encounter in their everyday activities. The white upper half of the hour and minute hands, as well as the arrow design at the top of the chronograph hand, are also a clever feature that helps the overall readability of the dial. Finally, the fact that all the writing and days are in German adds an extra touch of uniqueness.

Other interesting specs about the Sinn 157 EZM-4 chronograph

The 40mm case is hefty and masculine, just what's expected from an EZM watch, particularly the 157 variant. However, given that the EZM-4 case is 15mm, compared to 17mm of the majority of Sinn chronographs, it is noticeably lighter, weighing a total of 86g. Moreover, the case comes in two variants: the predominant steel one and a custom-order titanium one with only 25 units made. Sapphire crystal glass protects the dial, and an anti-reflective coating on the interior further enhances readability.

The Super-O2 (Pull-Twist) QR Titanium Watch Strap Straight End Quick Release is an excellent match for both the Stainless Steel and Titanium versions of the Sinn 157 EZM-4 Chronograph, complementing its dominant masculinity.

Sinn 157 EZM-4 is driven by the famous Lemania 5100. This self-winding mechanism is one of the best chronograph calibers. It is renowned for its high level of shock resistance, which provides reliability in the harsh conditions in which this tool watch is designed to operate. To top it all, the Lemania 5100 caliber is also famous for its long operating intervals and ease of serviceability.

A palette of possible alternative strap combinations for Sinn 157 EZM-4

Service and tool watches are not generally known for their compatibility with a wide selection of replacement straps. It usually stems from their rigid, often reduced case design, which does not allow for a wide selection of possible strap combinations. EZM-4 is an example of a German design school where function takes precedence over form. However, the dial design softens the prevailing rigid appeal.

The trick lies in the choice of colors. The prevailing black background is enriched with yellow, white, and orange details. Of course, the primary goal is the functionality of the hands and scales, as well as the overall readability of the dial. However, these subtle shades of corresponding colors allow for several interesting strap options that can turn this tool watch into a wearable timepiece in virtually any setting. The fact that it can fit both 20 and 22m straps additionally expands the pairing possibilities.

The subtle yellow color of the FKM Quick Release FKM29 Rubber watch strap is a perfect match for the yellow scale of the Sinn 157 EZM-4 Chronograph, softening the overall rigidity of the case and creating an unexpectedly gentle combination.

In Summary

Sinn 157 EZM-4 is a specially designed tool watch par excellence. Additionally, it offers more than that, thanks to its compatibility with a range of excellent replacement straps. Due to all this, and the fact that it has been in production for only four years, there is a limited number available on the market. That's particularly true for the titanium case variant.

All in all, for those who love authentic and reliable tool watches with a distinct German spirit built in, the Sinn 157 EZM-4 is well worth considering. Of course, that applies to both firefighters, for whom this watch is primarily designed, and everyone else who loves specialized tool watches.

Written by S.K. , images by Toni