The PRO-RING concrete-alternative manhole and catch basin grade adjustment system from Cretex Specialty Products is available in round, square and rectangular shapes. They are manufactured from expanded polypropylene, which is renowned for its strength-to-weight ratio, durability, chemical resistance and long service life under harsh conditions. One person can install the watertight system in minutes to within a 1/4 inch of finished grade. Where concrete rings break and may cause injury, the system eliminates the hazard, helping minimize the risk of injury. A 6-inch unit weighs 14 pounds and stands up to physical abuse. The system can dramatically help speed manhole installation and repair time. Manhole repair sites can be opened, repaired, and closed in one day, reducing overall costs. Angle rings are available to match slopes, eliminating the need for mortar and shimming. 800-345-3764; www.cretexseals.com.