Men's Watches

Type of Watch Strap- Bonklip



Truthfully, many people don’t really care about watch straps. Most of us only care about its functions, case, dial and the finishing of the watch(I am guilty of that too). In fact, watch straps is the most easily left out part of the watch.

Vintage leather strap genuine leather

That is why a lot of watch manufacturers purposely design the straps to be replaceable after a period of time. This is true for leather and nylon straps in the past as they age and undergo wear and tear.

An example of wear and tear from the Bretling 22mm leather strap


However, watch straps can actually increase the resale value of your vintage and classic watch. So maybe in the past, your watch cost you RM40, 000 (~USD 10,000) but after restoration, it can jump to RM100,000’s (~USD25, 000) or more. We will never know!!

IWC Mark 11 RAF military watch 1952




An example is the famous military watch, Mk. 11 from IWC and Jaeger-LeCoultre. While this is a classic and vintage navigational watch used during World War 2, it is actually the strap itself which increases its resale value in the watch market.

Mark 11 RAF series with Bonklip bracelet




For your information, the Mk 11 is using one of the earliest forms of a metal bracelet, known as the Bonklip. The Bonklip metal bracelet is so full of rich history, going back all the way to World War 2. It is not surprising that the Mk 11 with original Bonklip bracelet will fetch a high resale value.

Bonklip bracelet with the signature Bonklip carving

Bonklip bracelet with the original packing




During World War 2, pilots in the air force were able to fly to higher altitudes. Of course, at higher altitudes, the temperatures are colder in the cockpit. Plus, those days there is a lack of a heating mechanism. So what happens was there was a demand to provide the pilots and navigators with thicker, and warmer flight jacket.

RAF Shearling Flight Bomber Jacket


Longines 6B/159 Navigational Watch used by the RAF


So here comes the real problem. Those days, British men in the RAF were given the navigational wristwatch, Longines 6B/159 reference number. They wore it with traditional short pigskin strap. Because of its limited strap length, they usually wear the watch with its leather strap under the flight jacket.


The RAF has a tough time each time they want to uncover their watch to tell the time as it is hidden underneath the thick flight jackets. Also, it is almost impossible to navigate at the same time record the exact time with the conventional leather skin strap.



It is also harder to adjust the strap with the flight jacket on. Therefore, the Mark 11 with the Bonklip was designed to overcome this problem faced by the RAF. With the Bonklip, the user can wear the watch on the naked wrists as well as over their flight jackets.




To simplify, the Bonklip is a series of metal links joined together by bands. At the end link, there will be a special link with a hook, a unique fastening method at that time. There are gaps between the bands as well.

One of the earliest patent of the Bonklip on March 6, 1930


The design of the Bonklip allows the hook at the end link to be fastened to any of the gaps between the metal link. This flexibility means that the Bonklip is easily adjustable to different widths of the wrists. Also, its simple design allows the length to be adjusted easily without having to remove the watch from the wrists.


All the user has to do is to un-hook the end link and adjust the length to the respective gaps accordingly. Usually made out of stainless steel, it is one of the earliest mass-produced metal bracelets at its time, making it cheap.



Throughout the 1950s and 1960s, the Bonklip is heavily used in the RAF as it meets the requirements of the British Military. However, during the 1970s and 1980s, the Ministry of Defence issued a standard Def-Standard 66-4, which causes the Bonklip to be phased out.

The Bonklip will soon be replaced with the cheaper and more weatherproof, nylon strap known as the “NATO strap“.  If you want to learn more about the origin designing the Bonklip, click this article from

Classic Daniel Wellington with NATO strap


Also special thanks to for the comprehensive guide to all things Bonklip. The Bonklip is an amazing strap which if you have the opportunity to buy one, it will add value to your watch for sure. Don’t worry if you cannot find the authentic Bonklip strap, there are other companies which also manufactured straps, like Forstner for example.


Bonklip Bamboo Bracelet 18mm


Bonklip Bracelet 16mm


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