ESI Super Cap Seal XL 23 FT (2 1/8" Width x 1/2" Height x 23' Length) EPDM Rubber 2 1/8" width for mounting a truck cap or camper shell on a truck with extra wide bed rails and that weighs over 200 lbs. Fills all bed rail gaps. Complete kit includes seal, butyl tape, alcohol pads and detailed instructions High quality, long-lasting automotive grade EPDM rubber. Preferred by professional installers over PVC/foam seals. Excellent compression set resistance for maximum service life and vibration absorption Excellent compression set resistance for maximum service life and vibration absorption