I have 14 20X48 inch and 3 24X48 inch prefinished cement siding. They are snow white. 5/16 think.
Great for building a dog house or playhouse that you never have to paint again!
Very similar to this product:
https://www.menards.com/main/building-materials/siding/engineered-wood-sidi...
It does have grooves.
20X48 prefinished cement siding (By WJHS)
This offer has been gifted to someone and is no longer available.