Tri Basic Lead Sulphate (TBLS) is a white powder which finds extensive use as a stabilizer at high temperatures during PVC processing. The applications of TBLS include rigid PVC processing, manufacturing of cables and extrusions and calendaring operations. It is also used as stabilizer in extruded, calandered & moulded PVC products.

However, Tri Basic Lead Sulphate lacks lubricating property, and hence it is usually used along with a lubricating substance, mostly Calcium Stearate, Di Basic Lead Stearate or Lead Stearate. However, due to toxicity, Tri Basic Lead Sulphate is not used in articles that are likely to come in contact with foodstuff.