PATSTAB 1001 is a novel, antimony mercaptide stabilizer system for rigid pipes and pipe fittings applications. Optimum results are obtained when used in twin screw extrusion of pipes as well as injection moulded pipe fittings. The advantage of using PATSTAB 1001 is the low PHR levels as compared to leads and tin stabilizers. Best results are obtained when used with calcium stearate due to the exceptional synergy of the two materials. In comparison with lead stabilizers, PATSTAB 1001 gives much greater heat stability when incorporated with calcium stearate. The synergism of PATSTAB 1001 extends well beyond calcium stearate to all alkali and alkaline earth metal salts of organic acids. Improved U.V. resistance can be achieved by increased dosage of titanium dioxide in the formulation with PATSTAB 1001. Also the sulphur staining is much less than lead based stabilizers. At low temperatures PATSTAB 1001 performs very well as compared to methyl and butyl tin as well as lead based stabilizers.