The surface of the ramp is slippery in some places,and like sandpaper on others. This does not work well for the dog.  However,
that is easy to remedy by gluing a scrap of inexpensive low nap carpeting , using contact cement, on the surface of the ramp.
Otherwise , the slope, and general design works well, and it is sturdy. Actually, I find that the gluing on of carpet helps on all ramps
The type of carpet is crucial in order for the dog to be able to grip the surface.  I use a low nap, but with a texture, such as ribbing.