Grit Nonskid
Fiberglass grit-style nonskid offers good traction when dry but loses some grip when wet. While most of the water beaded up and ran off quickly as we increased the angle, the texture retained some water, and we believe this led to the reduced grip in our wet test of this surface.

Comments
To confirm these results, we tested fiberglass grit-style nonskid surfaces from other sources, but we found that Grady-White offers the best grip, if not the most gritty texture, in this category. 

Pros 
When dry, this surface offers just as much traction as diamond nonskid.

Cons
A tendency to hold minute amounts of moisture leads to  loss of traction when wet.