The Whirlygig riser/collar installation system is size accurate and enables risers and collars to be installed in minutes. Simply place a form on the manhole cone, trim the form to grade with a radial arm trimmer, place the manhole ring, check accuracy and pour redi-mix. Cast-in-place on site, the system streamlines installation into a process that works every time and produces a sturdy installation. 800/307-4263; www.wgig.us.