Methyl Tin Mercaptide SW-977 is such a good heat stabilizer of plastic product that has been used extensively in rigid PVC processing of rolling,extuding,injection molding and blowing molding,It has a good pigmenting property,transparency and thermal stability.The product applies to used in strict application of the stability and transparency requirements that apply to the FDA approved on pipes and food packaging. Technical parameter: Appearance clean and oiled transparent fluid Tin Content (%) more than 19.0 Chroma (Pt-Co) less than 50 Viscosity (25C Pa.s) 0.020--0.080 Specific Gravity (20C) 1.17-1.19 Sulfur Content (%) 11.5-12.5