Crafter Blue is a Hong Kong based strap designer and manufacturer that specializes in making custom curved end rubber and leather straps for a number of popular Seiko* and Tudor watches. At the time of this writing, they produce straps for the Seiko Sumo, MarineMaster 300, Shogun, SKX, Turtle and Samurai. They also offer straps for the Tudor Black Bay and Pelagos along with a “universal” rubber strap that has a straight end to fit any watch with 22mm lugs. I have owned the CB05 Curved End Rubber Strap for my SKX007 for over a year, this review will be looking specifically at the black curved end rubber strap but many of the characteristics carry over to their other rubber strap models.

The Crafter Blue strap is packaged in a simple clear plastic zip top bag with the brand’s logo printed in black. Inside is the strap along with a nicely made plastic credit card style 12 month International Guarantee Certificate with an embossed serial number on the front. The packaging is very basic and may be underwhelming to some, but in my mind the minimalist materials reduce waste and the cost to produce. You can’t wear the packaging, so why waste money on it?

My first impressions of the Crafter Blue rubber strap are very positive, especially compared to the factory Seiko Z22 strap. The vulcanized rubber is soft and supple to the touch (even with it being considerably thick). It measures 7.2mm thick at the lugs and tapers to 3.5mm thick at the ends. In comparison, the stock Z22 strap measures approximately 3mm thick but is much more stiff and plastic feeling due to the different rubber compound.

The Crafter Blue feels like it’s much higher quality due to its suppleness and flexibility compared to the stock Seiko strap option. Unlike some rubber straps on the market, Crafter Blue straps do not add a vanilla scent to the rubber compound to mask the natural rubber smell. The strap has no noticeable smell of rubber, chemicals or other not-so pleasant odors one might expect with a vulcanized rubber product. I’m not sure how they did it but it’s a big plus in my book.

The outside surface of the strap has a basic design of two parallel recessed lines that run the length of both the 12 o’clock and 6 o’clock pieces. This gives the strap a nice finished look without it being overly distracting in a way that may clash with the SKX’s tool watch aesthetic.

Before purchasing the Crafter Blue strap, I was concerned that dirt and grime would find its way into these recessed lines and need to be frequently cleaned out. My fear was all for naught because I have yet to notice any significant collection of grime on the outside surface. The six o’clock piece of the strap offers 16 adjustment holes spaced about 5mm apart to allow a comfortable fit for most wrists up to approximately 8.5 inches in diameter.

On the underside, Crafter Blue has added dozens of small diagonally recessed lines to both pieces, presumably to allow the circulation of fresh air against against the skin to dry sweat and water. As with most rubber straps, moisture will never be able to completely dry and after a full day on the wrist I noticed a slight smell when taken off. If this is a concern to you, just quickly rinse and dry the strap every time you wash your hands which should eliminate most odors. I have also noticed with everyday wear these small diagonal lines on the underside of the Crafter Blue strap tend to accumulate grime relatively quickly. This is to be expected with most straps and is easily cleaned with soapy water and a toothbrush on a weekly basis or as needed.

Crafter Blue’s stainless steel hardware is just as high quality as the rubber in their straps. The buckle and sliding keeper are made from tough 316L stainless steel and both have a nice satin finish. The buckle, which has drilled spring bar holes, is held in place by a 20mm stainless steel spring bar for easy removal and replacement if needed. The sliding stainless steel keeper is the only one on the strap and is built quite large. It measures approximately 22mm wide, 13mm long and 10mm thick to accommodate the excess rubber strap.

The exterior of the keeper features the word “PROFESSIONAL” stamped widthwise. I am not a professional diver so I’d prefer if it wasn’t stamped on the keeper but I can understand why it’s there since this strap is designed with the professional in mind. The underside is very nicely welded and is nearly perfectly smooth so there is no fear of scratching your skin or pulling hair. It holds the excess strap well enough, but I have found it to occasionally slide up during the day and release the excess. This is not a deal breaker but can become annoying if it happens often.

The main difference between the Crafter Blue strap and most others is the custom curved ends that fit snugly against the SKX case. The curved ends create a seamless transition from the strap to the case, making it look as if the strap and watch are all one piece. Crafter Blue’s attention to detail is evident here as finding the correct curve measurements and contours must have taken some time and lots of trial and error.

Their hard work has really paid off because there are no noticeable gaps or inconsistencies where either the 12 o’clock or 6 o’clock pieces of the strap meet the case. I much prefer this seamless look compared to normal straight end straps that leave a gap between the strap and case. To ensure durability, they molded hard plastic into the curved ends where the 22mm spring bars go through.

This ensures the Crafter Blue’s curved rubber keeps its shape and it adds protection to prevent wear on the connection between the strap and lugs. One thing to keep in mind is the factory Seiko 2mm thick spring bars did not fit through my particular strap holes. I had to use 1.8mm thick spring bars that I had on hand.

While being worn, the Crafter Blue strap naturally curves around your wrist making it incredibly comfortable for a relatively heavy diver’s watch. This is thanks to the curved ends that force the strap to follow the downward curvature of the lugs and into a wrist shaped stance even when you’re not wearing it.


The Crafter Blue CB05 curved end rubber strap is a wonderful choice for someone looking to change the look of their Seiko SKX while still allowing it to be used in water. It takes this already amazing watch and adds a level of refinement and uniqueness to make it your own. This strap retails for $65.00 USD on Crafter Blue’s website and is available in black, blue, orange and yellow.

Also go check out all the Crafter Blue Straps on Amazon!

4 thoughts on “Crafter Blue Strap Review: Seiko SKX Curved End Rubber Strap (CB05)”

  1. Good review! I do have a question about the smallest it can fit, where you mentioned it can fit up to 8.5 inch wrists. I find that most of the rubber or silicon straps are long due to the aspect of using it for diving. I have yet to find a rubber strap made for small wrists in mind.

    Reply
    • Barton’s Elite silicone straps come with two length options, and the smaller one just about fits on my 6.75″ wrist. You would probably have to use the larger one on a 7″ wrist.

      Reply
  2. The supplied spring bars failed twice on my samurai, I drilled larger holes in the band to fit the Seiko fat bars and that took care of the problem. Ultimately I ordered the Seiko rubber strap that was considerably more comfortable on the wrist.. just my two cents

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