Gruppo Gamma Peacemaker PN-20 (Swiss SW219‑1 Mvmt)

We also carry a green dial version of this watch, as well as a centered second hand variant.

Peacemaker PN-20 Overview

The 43mm Gruppo Gamma Peacemaker PN-20 dive watch ticks all of the boxes for us, with a vibrant yet sophisticated blue and gold color palette, a stunning blue fumé gradient sandwich dial that subtly darkens towards the edges to add a greater sense of depth that is accented by the magnification effect on the edge of the boxed sapphire crystal, a case made from the most sought-after marine-grade bronze, a highly desirable Swiss Made hand-wound movement with small seconds that adds to the vintage vibe, two hundred meters of water resistance, double that of many other dive watches, and a generous application of Swiss SuperLuminova lume, making this one of the most elegant yet practical tool watches to come from this microbrand.

All of the hallmarks we've come to expect from a Gruppo Gamma Peacemaker are here in the Peacemaker PN-20, from the renowned quality of the build that you can just feel when operating the crown, to the improved accuracy from their watchmaker, with many watches regulated between zero and few seconds per day accuracy, and of course Gruppo Gamma's well respected homage to Italian dive watches of the 1930s to 1950s that is married with Gruppo Gamma's own unique touches and design language that help set these watches apart and make them so special.

We particularly love the decorative aged bronze look of the ring inside the sapphire crystal exhibition case back, which very much reminds us of the attachments on a vintage dive helmet, as well as all of the little touches such as fully drilled lugs for easy strap changes, and the color-matched watch multi-tool that includes a pin push tool to easily pop out those straps, a spring bar tool to help insert new straps, and two screwdrivers, one of which can be used to easily remove the bronze buckle, in case you'd like to use the bronze buckle on a different pair of straps.

CuSn8 Bronze

Why CuSn8 Bronze

CuSn8 bronze is always considered the premium choice and industry “gold” standard when it comes to bronze watches, despite being considerably more expensive than alternatives such as aluminum bronze or even brass, that one can often find in lower spec'd and less desirable timepieces. This is for two important reasons:

1. It's a corrosion resistant^† marine grade alloy, perfect for a bronze dive watch!
2. Bronze watches are all about the unique patinas that can develop over time, an oxidization layer that can help protect the watch as well as give each watch a subtle unique “aged” look as it changes color. CuSn8 bronze is particularly admired for it's ability to develop a rich deep brown patina compared to say aluminum bronze, which tends towards a less desirable lighter reddish brown.

Little wonder then that CuSn8 bronze has been the go-to choice for many famous luxury brands such as Bremont, Panerai, and IWC, to name just a few.

Customizing Your Patina

When newly manufactured, CuSn8 bronze has a warm gold-like color, a shiny golden brown which looks awesome, and is easily distinguishable from the greener hues in some other alloys. As it is exposed to the air, (or water,) it will start to develop a patina. Spotting is possible in new watches where parts of the watch have started to patina but other areas may still be more gold-like. Given time, the entire case will develop a more consistent patina that can give rise to some wonderful looks. However, sometimes you don't want to wait months to fully develop your patina, so we have one suggestion that can shorten things to a matter of minutes or hours instead:

Taking the egg yolk from a hard-boiled egg and placing it in an airtight container with your CuSn8 watch head can introduce a rich brown patina, which has the added bonus of being a protective oxidization. Care should be taken to avoid contact with the egg, and we would recommend having the watch raised on the sapphire crystal and steel exhibition case back so all bronze areas of the watch have a uniform exposure. Keep a close eye on the watch and remove and rinse under cold tap water open once you get the desired color. Then you can burnish or lightly polish it with just a microfiber cloth, which will help slow down any further changes.

Other colors are possible, and there are plenty of YouTube videos that detail the use of different household products such as vinegar. However we do recommend researching those carefully first as some combinations can introduce a corrosive green finish.

Resetting Your Patina

If you don't like the color or really love the golden look and want to remove any spotting, you can soak the watch head in lemon juice. This is the method with the least amount of work, but one you should avoid if the watch is not new as the dive seals may have aged and need replacing.

Two alternatives are: use a cheap [abrasive] toothpaste and toothbrush with a little water, which is good for removing light spotting but difficult for anything more, or use a Cape Cod Cloth, which is highly recommended and the process we follow in-house.

Maintaining Bronze Watches

When swimming with your watch, if you are in a pool with chlorinated or chemically treated water then we strongly recommend rinsing the watch in cold tap water afterwards to wash off any chemicals. We also recommend a quick rinse after salt water bathing or after excessive sweating too.

As with all dive watches, don't forget to always keep the crown fully screwed around water. Always keep the crown screwed down except when winding or adjusting.

It's also always worth mentioning that no watch should ever be introduced to a sauna, steam room, or hot water, such as a hot bath, hot spring, or hot tub. This includes all dive watches and is because the air inside the watch case can condense into water droplets that will most likely severely damage the mechanical movement fairly quickly. If your movement has been exposed to moisture, it should immediately be serviced.

^† CuSn8 bronze is more corrosion resistant than most other bronze or brass alloys, but like other metals, can corrode when exposed to some chemicals.

Watch Specifications

• Type: Microbrand dive watch.
• Reference: Gruppo Gamma Peacemaker PN-20.
• Color Scheme: Blue dial with vintage cream markings in a bronze case.
• Water Resistance: 20 ATM / 200 meters / 660 feet.
• Diameter: 43mm, excluding crown.
• Height: 13mm.
• Lug Width: 24mm.
• Lug-to-Lug Length: 52½mm. The photographs of this watch being worn depict a 6½ inch (16½cm) diameter wrist, the minimum size we would recommend.
• Crown: Marine grade CuSn8 bronze screw down crown.
• Case: Marine grade CuSn8 bronze with brushed finish and fully drilled lugs.
• Case Back: Marine grade 316L stainless steel with  scratch resistant sapphire crystal exhibition window that showcases the hand-wound Swiss movement.
• Dial Type: Blue gradient fumé sandwich dial with small seconds.
• Dial Glass: Scratch resistant boxed sapphire crystal with anti-reflective coating.
• Lume: Swiss Super-LumiNova Old Radium vintage lume color with a green glow. When initially excited, the lume may initially briefly glow off-white or cyan.
• Straps Included: 1x pair of color-matched blue rubber accordion dive straps that taper from 24mm to 22mm at the buckle, with matching CuSn8 bronze buckle and tang. 130mm and 80mm strap lengths.
• Tools Included: A color-matched multi-tool is included. Both ends can be unscrewed to expose a watch tool at each end. The tool can also be unscrewed in the middle to conveniently be split apart into two tools. The tool tips can be pulled out and are double sided, giving a total of four different tips:
  2x screwdriver tool tips, 1x spring bar tool tip, and 1x pin push tool tip.
• Movement: 24 jewel Swiss Sellita SW219-1 hand wound movement. Please note there is a ghost date position on this movement so you will need to pull the crown out to the second stop position in order to adjust the time.
• Improved Accuracy: This movement is specified to run with an accuracy of between 0 and +- 12 seconds per day when new, measured as an average of all positions. In practice we've found that many of these timepieces seem to have been regulated by Gruppo Gamma for an even better accuracy, typically between 0 and just a few seconds per day when measured dial-up.
• Oscillation: High beat 28,800 BPH, (8 ticks per second.)
• Hacks: Yes.
• Hand Winds: Yes.
• Automatic Winding: No.
• Power Reserve: 45 hours extended reserve.
• Manufacturer's Warranty: Coverage against manufacturing defects for 2 years on this watch, and 1 year on the included watch straps. The Microbrand Store is a Gruppo Gamma Authorized Dealer.