A 1/2" seam has been made around the perimeter of the sail.  The basting adhesive is on a paper strip that comes on the roll shown above the sail.  The 1' ruler shows the scale.  I should probably say here that the SailRite company, the maker of the cloth and basting tape, does not recommend using basting tape to replace sewing.  On the other hand, on the back of their catalog is a lovely picture of a set of sails made with just basting tape with a testimonial of how well it works!  PS It is a lot easier and faster than sewing!