May I ask if that is an original Seiko bracelet? And if so what's the article number? Looks almost vintage.
Alas, it is not a Seiko bracelet. The only OEM bracelet I know of that will fit the watch is the stock bracelet for the
SRPJ81. You
can order that bracelet from Seiko customer service at 1-800-722-4452. I don't know the part number, but they can look it up given the reference. I was quoted a price of more than $100. Seiko bracelets, at least for the Seiko 5 line, don't seem to have a very good reputation (I've never seen one in person), so that seems rather excessive. Also, that OEM bracelet is a three-link oyster style, and I really wanted an Engineer's style bracelet. As you noted, it has a bit more of a vintage aura which I like, but it also seems to pair very well with pilot watches, as
Laco and
IWC (among others) recognize.
The bracelet I have is a generic Asian one available from multiple sellers on eBay, Ali Express, etc.. I paid less than $15 for mine on
Amazon. There are three caveats worth mentioning, however:
1. As delivered, the bracelet is highly polished. Unsurprisingly considering the price, it's not done especially well. But even if it were finished very nicely, I don't like polished bracelets. They're too blingy for me. I gave my bracelet a satin finish using a bucket of sand and a plastic funnel. (Stream a funnel-full of sand onto the bracelet from a height of a couple of feet a dozen times or so.) Scotch-Brite also works well if you prefer a linear brushing instead of a satin finish.
2. The spring bars included with the bracelet are 1.6mm diameter. Those work fine with the flat end-links that are attached to the bracelet on delivery. If you swap those end-links for the optional curved end-links, however, 1.6mm is too thick to pass through the center links that are inserted into the end-links. You need 1.4mm diameter (or smaller) spring bars to use the curved end-links.
3. The curved end-links are not a perfect fit for the case. I was able to reshape them a bit with needle nose pliers, and I think they look reasonable, but it's still not perfect.
On the positive side, the 50垄 pin removal tool included with the bracelet actually lasted long enough for me to resize the bracelet and swap the end-links. (Everything uses split pins.)
I should add that, finishing aside, the bracelet is actually quite nice. The links are solid (not folded), and butterfly clasp is milled (not stamped). As with most butterfly clasps, there are no micro-adjustments and no half-links, but I had no problem getting a perfect fit as the links themselves are quite small with a pin-to-pin spacing of 9mm. It's well articulated and the inside surface is pretty soft against the wrist.