... no harsh noise8,One-time molded, durableApplications:1,water grates, trench cover, tree pool cover, retaining the tree board, ditch ... cover,retaining the tree board,ditch cover,trench drain grating,gratings trench cover BMC 5,trench covers, manhole sets, well base, the ... water company covers, midori composite trench covers easy to handle, cost effective,non conductive,non skid ...