The needle of system UY 121 GBS has a medium ball point for working knit fabrics, without damaging the loops. It is used in industrial overlock, coverstitch and safety-stitch machines for elastic knit fabrics. Suitable machine classes are found, among others, at Union Special (classes LF, 31100 E, K, L, 51300 Z 3075, 52700) and Singer (classes 678, 2700, 2800, 678 - B).
The available needle sizes are used, among others, for fine, light jersey and tricot fabrics. As sewing thread, a matching thickness is usually recommended depending on the needle size chosen, e.g. from Amann Serafil or Rasant; for very stretchy seams, a texturised thread also works well. The ball point glides between the loops instead of piercing them, keeping the seam clean and undamaged.
