Detailed Product Description FRP/GRP, SMC , DMC/BMC Manhole covers, gratings,gully tops and Tress grilles, and ... follow advantages:1.Anti-theft, the materials FRP/GRP ,SMC, DMC/BMC are not be used again.2.Anti-corrosion, the ... materials FRP/GRP ,SMC, DMC/BMC have high anti-corrosion.3. Long use-age life ...