The 20-foot triangle shade sail by Colour Tree is amazing. 
I have tried other shade sails and by far the quality of the material is fantastic. The hooks are a good size and easy to attach, I choose the brown color and It is not a solid brown but a weave of a dark brown, tan and beige and the shade it gives is unbelievable, it is also a lot  cooler under it than you would get with a beach umbrella. I was so pleased with it that I ordered a second one to cross over and give the children more shade and play area. Highly recommend.