Just to add (in case you dont already know)
Omnigrid are the best ... clear markings that show easily on most fabrics.
AVOID like the plague any rulers with
RED or
FLUORESCENT YELLOW markings...
The firsts markings don't show on most fabrics, the second completely obscures the fabric underneath as the entire ruler seems to have a weird sickly yellow tint.
You will also need to add some anti-slip feature to your new ruler; I recommend adding sandpaper dots on the underside of your ruler to hold it in place, just be careful where you position them ... Ask me how I know?!?
Omnigrid also make Omnigrip which have integral anti-slip markings ... tho' some say this is not as good a thing as it seems as it makes the markings too thick ...