So I ordered two sets of o-rings, 70A (firmer) and 50A (softer) to do a
dental-band mod.
I ended up liking the 70A more, so I'm selling the softer set, because otherwise they would be lying around. Note, I did take 5 of these to use on some leopold keys, so the bag has 120, not 125, but they should still be enough for a full board.
Here's the product link on amazon:
http://www.amazon.com/gp/product/B0051XWXCESelling for 7 dollars, shipped in a cushioned first-class envelope. The bag's been opened, but they will be placed in a sandwich bag and should be fine for transport. Good to try without having to pay another 5 in shipping from McMaster's or the 2 bucks from Amazon.