In my search to replace my rapidly disintegrating iSi silicone spatulas, I ordered one of these Rose Levy Berenbaum reduction spatulas. (eG-friendly Amazon.com link)
Not exactly an iSi replacement but it could come in handy. It's long and narrow. The leading edges are nice and thin and it's graduated to provide a rough measure to note when reducing liquids.
Unlike the photo on Amazon, mine doesn't have white lettering, and I don't recall seeing that when I ordered it, though it's been quite a while. Amazon reviewers report the same. Just as glad, as I'd be worried about it chipping off.
The graduations appear on both sides of the spatula.
Edited to add that I used to put a mark on a wooden chopstick for this purpose though I sometimes missed that there was already a mark on it and wasn't sure which one was correct!
