Spanner wrenches ?

I didnt know there was two types till today. From what I can find, adjustable hook, you can make the hook bigger or smaller. Adjustable pin, means you can put a round pin or a square pin or different sizes of pins.

It may be they are all one in the same with two different names as well.

 

hook is rectangular, for nuts that have slots machined in the outer circumference (as used on wheelbearings)
pin has round pins, for nuts that have holes drilled in the outer circumference.

Google images for "skf nut", and you will see what I mean. Most of them have the slots, but some are just round with holes drilled in them

Maybe this explanation will help..... or just cause more confusion:
http://www.circuitousroot.com/artifice/fitting/mechanics/tools/pin-wrench/