A unique copolymer warp yarn sizing agent for Cotton, Rayon, Modal Polyester and Blends of Polyester/Cotton/Viscose Spun yarns. Heavy fabric constructions are easier to weave at low size add-on using SizeMagik-LP4. Low add-on also permits greater protection on high speed looms expensive reeds and sensitive mechanical parts life. Better film properties of the product provide the lower warp breaks and it improve the finished products quality. Reduced dropping level in sizing and weaving it provide more comfortable working conditions and reduce maintenance cost.