Manhole covers from Huber Technology are available in 304L or 316L stainless steel. The durable covers offer absolute corrosion protection by pickling and passivation. They provide permanent safety for people and the environment. The weatherproof square-type covers can be used in well shafts, shafts at sources, steam ventilation shafts, wastewater shafts, sump shafts and cover shafts. Options include an air vent, insulation, odor control carbon filter and rubber gaskets. 704/949-1010; www.huberforum.net.