Risers and Sumps Winnipeg | Winnipeg Concrete Suppliers | Thrifty Winnipeg Meta Description: Designed to clamp sewer discharge lines, these risers feature PolyLok mandrels that provide an excellent, flexible seal with no need for glue or grout. However, we strive to exceed your expectations. We ensure rigorous quality control standards through our quality-controlled production environment. keywords: limestone supplies winnipeg,limestone winnipeg