Custom springbar for Seiko SRP639K (Monster Tuna) on mesh bracelet

Edit : add more photos (10.3.2015)

Hi guys, i just installed a mesh bracelet on the Seiko SRP639K (nick named Monster Tuna). It sure looks good on mesh bracelet !

Below the photo :

Photo 30-1-15 5 45 29 pm

The reason for this post is to recommend and suggest the suitable springbar when installing mesh bracelet or leather strap.
The mesh bracelet has a rather small lug hole with max diameter of 2mm. Most commercial springbar comes either in diameter of 1.5mm or 1.78mm but its pin head are only 0.8mm to 1.0mm. These undersize springbar end pin will damage the Seiko lug holes in the long run.

See below pic :


For leather strap you may get away with it by forcing the Seiko fat springbar into the strap lug and stretch the leather. The SRP639K has drilled thru lug, so its no issue removing these fat springbar. But for mesh bracelet in my opinion, the best option is to use these custom 22mm springbar of correct 1.2mm pin head, body diameter is 2mm (fit nicely into the mesh bracelet). See photos below for better understanding.

Photo 30-1-15 6 12 33 pm Photo 30-1-15 6 11 08 pmPhoto 30-1-15 6 13 01 pm Photo 30-1-15 6 13 21 pmPhoto 30-1-15 6 13 52 pm

You can buy them here. They are also suitable for use in Seiko SKX, 6309 driver watch. Being double flange, it will be easier to remove too !

Price : $15 for 2 pair (4 pieces) inclusive of shipping
Contact me for paypal details.

Interested, pls contact me here or email me at


Please help support as its costly to custom made mold and fixture for these springbar for specific design. I have paid up front for it and hope it benefit all.


Oh ! if you need a spare set of fat springbar ! Let me know, i have them too.

Seiko 20mm and 22mm fat springbar [$10 for 2 pair)]

Photo 30-7-14 4 00 50 pm Photo 30-7-14 4 01 30 pm

Thanks for reading.


Installed another Tuna Monster with the custom springbar and PVD mesh. Piece of cake !

Photo 6-3-15 3 32 17 pm Photo 6-3-15 3 32 55 pm Photo 6-3-15 3 33 19 pm




  1. Where did you pick up the watch strap?

  2. Ohh, those mesh bracelet ?
    They are available at our local watch retailer store for $35.

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