ULT black o-ring: what size?

[Wilko]

I have just used up the last little black o-ring for my ULT (having three automags, all with an ULT, I drown in all sizes of AGD o-rings, except for this one). I have tried to find a replacement for this o-ring, so that I can buy a dozen or so at the same time, instead of buying the complete o-ring kits from AGD just for this one little o-ring.

The thing is, I don't have a clue what size or material it is. Being Dutch, I have difficulties adjusting to the imperial system, so converting the size I measured in metric to inches is a challenge for me.

I was hoping that someone here could give me the correct size (Durometer size?) and material (maybe BN90 or BN70?) so that I could order them somewhere online.

The o-ring I mean is the small black one in the ULT:
http://kayaker.nl/pb/ult-oring2.JPG

This is the (rough) size on the calipers (? Don't have a clue what they are called in English...):

http://kayaker.nl/pb/ult-oring.JPG

If you know where I can get just a dozen or so of this size of o-ring for a decent price, from a shop that also ships to Europe, I'd love to hear it!

Thanks in advance!

[Spider-TW]

Well, it's a -001 or a -002 :rolleyes:

http://www.marcorubber.com/sizingchart.htm

I would guess -001, but idk if I would buy 300 of them...

http://www.allorings.com/cgi-bin/CatalogMgr.pl?cartID=b-5842&SearchField=category&SearchFor=Buna+O-Rings&template=Htx/order_buna.htx&hdr=Order+Buna-N+O-Rings&displayNumber=369

They charge a pound of shipping though, must be some heavy o-rings. :argh:

I've wondered about these myself.

[Wilko]

Well, it's a -001 or a -002 :rolleyes:

http://www.marcorubber.com/sizingchart.htm

I would guess -001, but idk if I would buy 300 of them...

http://www.allorings.com/cgi-bin/CatalogMgr.pl?cartID=b-5842&SearchField=category&SearchFor=Buna+O-Rings&template=Htx/order_buna.htx&hdr=Order+Buna-N+O-Rings&displayNumber=369

They charge a pound of shipping though, must be some heavy o-rings. :argh:

I've wondered about these myself.

Thanks! That was a lot more helpful than you might have thought!:)
I found the size in milimeters through your first link, and that made me measure it and realize that it is indeed -001 sized.

That brings the second question: Should I get BN 70 or BN 90?

Considering I was quoted 2 US$ per o-ring when ordering 10 of them from someone here on AO, I'm probably better off when ordering them elsewhere and go for the larger amount at once.

You were also right about that pound weight: that allorings site charges 90 US$ to deliver that 10US$ one pound bag to the Netherlands, with no cheaper option offered. Not what I had in mind. :-)

Edit: just called with a lady from the paintballorings site, and she quoted me 3 US$ for 100 of those -001 size orings, with 4,50 shipping. That sounds more like it! :-)

[Spider-TW]

I think the 70s should be fine. I can't see them being hard. I've used soft buna on my RT on/off in a classic valve for a couple of years now (iirc).