These watch band buckle extenders are great for watchmakers because they ensure that your watches will always fit perfectly, even if you have lost the links or they have been discontinued. These watch band buckle extenders are generally used on tri-fold clasps, and are most popular in Seik0 watches. The watch band extenders are the same size on both sides and are attached on one side to the clasp and the other is attached to the band with spring bars.