One question that we've received frequently regarding our CTS straps is: Why does the Regular CTS come with 3 sides, while the Curved CTS and Integrated CTS (i.e. PRX, BB58 etc) come with only 2 sides? To explain that, we have to first understand why the Regular CTS came with 3 sides.
Regular CTS comes with 3 Sides per Set
When we first launched the Regular CTS, the idea was to provide 3 sides per order, even though you needed only 2 sides to wear the strap, leaving 1 side as a spare. The 3rd side was included for 2 reasons:
Reason 1: To accommodate for watches of the same lug width but different lug-to-lug distance.
Reason 2: To act as a spare in case the first 2 sides were sized and cut incorrectly.
Most people understand Reason 2 on sizing it incorrectly - once you've cut the strap, there's no turning back! However, it is actually Reason 1 that is a bigger factor in why we've included a 3rd side.
As the Regular CTS has a universal fit, it can be used on any watch as long as the watch had the same lug width as the strap. And a big value proposition of our straps is the quick release spring bars, which allows you to easily swap them around. This does not just mean one watch, multiple straps - it can also mean one strap, multiple watches!
However, given that the CTS straps are cut-to-size, if you had sized the strap for one watch, any other watch you swap the strap to would need to have roughly similar lug-to-lug distance, otherwise the strap will not fit. Hence, the 3rd side was included to allow you to still use the CTS strap with a different watch that had the same lug width, but a significantly different lug-to-lug distance.
Confused? Let's compare these two watches for a more concrete example - the Grand Seiko SBGH267 Whirlpool, and the Cartier Tank Must Large. While they both have a lug width of 19mm, the Grand Seiko has a lug-to-lug distance of 47.5mm, while the Cartier has a lug-to-lug distance of 33.7mm. That's a difference in lug-to-lug distance of 13.8mm!
If you had bought a 19mm CTS strap and sized it for the Cartier Tank, and now you tried to fit the same strap on the Grand Seiko Whirlpool, it would be too short and too tight. However, with the included 3rd side, you can now cut the 3rd side to a different length to fit the Grand Seiko, and you now have a set of CTS strap that can fit both the Grand Seiko and Cartier!
Curved and Integrated CTS comes with 2 Sides per Set
Why then do our Curved and Integrated CTS come with just 2 sides per set? Because Reason 1 is largely irrelevant when it comes to Curved and Integrated CTS straps!
With Integrated CTS, the strap will only fit on the watch that it was meant for, and hence there will not be any situations where there are multiple watches of different lug-to-lug distance. Hence, there is no need for a 3rd side.
With Curved CTS, while there are a small range of watches that the strap will fit, they are mostly of the same range of lug-to-lug distance, and hence do not necessitate the need for a 3rd side as well.
While Reason 2 on the 3rd side acting as a spare is still relevant, it is insufficient for us to include a 3rd side just for that reason alone.
We hope that this article will help to explain why some CTS straps come with 3 sides per set, while some come with 2 sides per set. If you have any further questions or feedback, please reach out to let us know, and we'll be happy to clarify.