Numeric index for Zcatalog searches?

I never had to do this before, do we have an Indexes for number (float/int) for Zcatalog so that you can compare number and in a Collection say, give me all items with value x > 5? There's a lot for comparing and advanced searching of Dates in Zope Plone, but do we have the same for simple numbers?

I do this:

items = portal_catalog(
    {'age': {
        'range':'min:max' }

look in the catalog docs

Thanks! I missed that snippet in the Plone documentation. So it seems FieldIndex supports number and allows for comparison/range operations on them. I was looking it up in the ZCcatalog/Zope documentation and Fieldindex is being documented as only being able to find 'unique' fields.

It does not only apply to number but to any ordered data. TextIndexNG3 uses the underlaying functionality of the ZODB - BTrees in particular - for searching for example all strings between "aa" and "cc".