... - Polypropylene materials - "Heat-set" after winding to stabilize - Resist mortar, oil, or mildew and will not absorb water This type ... stabilized with a post-winding heat set Not affected by mortar, oil, or mildew and will not absorb water Breaking ... Monofilament Twisted 3-Strands Polypropylene Mason's String Line features mortar-, oil- and mildew-resistant construction, ideal for staking out ...