Manhole riser rings from LADTECH can be installed in minutes. The rings nest together, and include a 2 percent slope ring and a 1/4-inch spacer ring for a precision fit. They’re made of high-density, lightweight recycled polyethylene, meet AASHTO’s HS-25 axle-loading spec, and are impervious to H2S corrosion that destroys concrete. 877/425-1252; www.ladtech.com; Booth #1131.