Love, love, love these reinforced corners (I will Never buy another sail cloth without them they are that fantastic!!) The corners are normally where a combination of tension & cafing on metal hardware attachment points occur causing regular grommets on your sail cloth to fail but not on these beauties- this is solid metal corner pieces that really hold up in all conditions. This mesh fabric sail is also far superior to normal sail cloth fabric in that normal water & wind pass through it rather than pond & stain on fabric sail cloth and the reinforced steel cable sewn into the edge seam help keep the shaping consistent & the tension uniform.