Home > Threads > Seraflex Elastic Thread SERAFLEX is the perfect sewing thread for highly elastic seams. Due to its innovative raw material PTT (37% renewable raw material) an elongation of approx. 65% is achieved, making all seams highly elastic. SERAFLEX makes especially the straight stitch extremely stretchable, in the best case even a doubling of the seam elasticity can be achieved compared to seams with conventional sewing threads. Due to its extremely elastic properties SERAFLEX is primarily used for clothing, e.g. as sewing thread for sportswear, outdoor, women's, men's and children's clothing as well as for lingerie and underwear.