Because the self levelling fluid in my w126 needs a little top up and I have both of the fluids mentioned in my first post in my shed. Thanks for clearing things up for me.
both described as hydraulic oil for soft tops CLK and SL in 2001- my guess they are both the same-HOWEVER -it may be the seals in the units have different elastomers so unless MB tell you they are equivalent---- use the recommended one for your model.