The T-Slot adapter sits 1/2 inch above the surface of the cross bar. The total height of the FatCat when using the T-Slot adapter will be 3.5" from the top of the crossbar to the top of the ski mount.
Height above the roof will vary depending on the tower being used and the your specific vehicle so we are unable to provide total height above the roof.
If you have additional questions please contact us here, or by phone at 888-925-4621 during business hours.
