FC series stud-hole flange protectors insert easily into flange bolt holes without using fasteners. Made of low-density polyethylene to resist degrading effects of weather and petroleum. Available in sizes to fit pipes from 1/2 to 12 in. and for flanges from 125 to 600 lb.
Niagara Caps and Plugs, (800) 458-0465, www.niagaracapsandplugs.com