There are 5 standard profiles available in the GTT for Offset range: S, M, L. XL and XXL.  It is very easy to make a selection, dependent upon your application.  If you are not certain which profile suits your application best, you can make use of the live banded roll test.  Apex holds several banded rolls in stock for most of the common machine types.  Ask your local Apex technical representative for more information on this unique service.