I have 2 large sunshade tarps. One is dark green 10'.  This one (that I'm reviewing here) is a 12 foot sunflower yellow.  It's an excellent product that my cats love jumping onto from the roof and using as a giant hammock.  After a year of rough treatment, they have torn it, but the grain-wise tear has been slow to progress; I think I can repair it.  Although both my shade sails keep out UV rays and create some shade, the dark green one does a much much better job of cooling and shading underneath it.  I squint under this golden one.