Seam rippers come with a sharp end and a shorter protected end. The pointed end is made to insert into a tight seam and cut he first thread. The shorter ball end is then inserted between the cut stitches, and the seam ripper is pushed along the seam line. The ball end protect the fabric from damage while cutting the threads in the seam. Be careful not to accidentally cut through the fabric with the sharper, longer end while opening up and removing a line of stitching. The area between the two points is very sharp and can also be used to cut open buttonholes, not just fabric seams. The grain (lengthwise) of woven fabric does not have any stretch, so it is easier to remove a seam with a seam ripper on the grain than on the crossgrain (across the width of the fabric, from selvage to selvage).