Seal Kit for 3.5" Welded Tube Cross Cylinder This seal kit fits our Welded Tube Cross Cylinder Rod Seal: Reliable double lip u-cup Piston Seal: TFE Teflon Glass - Filled with O-ring Tube Seal: Nitrile rubber O-ring for long life Available for 2", 2.5", 3", 3.5", 4"