The spanner is sort of a hook shape and is maybe not an exact match for every shock but should be usable between most brands.
http://images.google.com/images?q=sh...-8&sa=N&tab=wi
This link to a google image search should explain quite a bit.
You could also make your own tool without too much trouble, or modify another tool. If you're worried about scratching up the shock use a rag.
I've used all kinds of things in a pinch.
-Ben
