NDS JUMBO RECTANGULAR OVERLAPPING COVER ONLY:
The NDS STANDARD SERIES 13"X20" rectangular valve boxes overlapping covers prevent dirt and grass from settling between body and cover. UV inhibitors are added to prevent discoloration and deterioration; such as cracking or blistering.
- Injection molded of recycled polyolefin material with a melt index between 10-12.
- Coloring and UV stabilizers are added, along with processing lubricants when needed.
- The cover seat shall have 16 structural ribs on the underside of the seat, each with a minimum thickness of .250"
- The 13"X20" cover shall have a average thickness of .250"
Do you have a cover with the above dimensions?
I'm not sure what the material is, maybe some kind of heavy plastic.
The rains have been so heavy in my area, though, that I put a very heavy rock on top of it to keep it from floating away.