This is replacement tacking material used when replacing your convertible top. This material is used on most cars for the rear tacking rail, on older cars this can be riveted to the top of the body for the top to staple to. It is 7/8" wide and 1/4" thick plastic material that is made to replace the old tacking strips on your car. Your original tacking material could have been a compressed cardboard or any number of different materials, they all fall apart after time and the new plastic tacking strip holds staples better and will never rot away.
This material is sold in an 8 foot roll.