TRIM-LOK? - 3/8 Inch Thick x 3/8 Wide x 100 Ft. Long, EPDM Rubber Ribbed Seal with Tape - 68946219 - MSC Industrial Supply
Rubber-Cal Recycled Rubber Sheet- 60A Durometer- Smooth Finish- Backing- 3/8-in Thick x 12-in Width x 12-in Length- Black (Pack of 4) in the Rubber Sheets & Rolls department at Lowes.com
3/8" EPDM THICK RUBBER ROLL – American Material Supply
Hillman 3/8 in. Inner Diameter - 5/8 in. Outer Diameter Rubber Grommet 55055 - The Home Depot
Rubber-Cal "Recycled Flooring" 3/8 in. x 4 ft. x 9 ft. - Black Rubber Mats - 48 x 108 - Overstock - 8238730