I rarely review products but I can't recommend the wire anchors for concrete fence posts - along with the gripple tension system enough! I have a garden surrounded by fencing on three sides and there are now very few concrete posts that don't have anchors on them. They are so easy to fit and are incredibly robust. Some of mine have been up for three years and there is no sign of weathering or ageing. The gripple tension system is just as easy to use and just as robust - I haven't yet had to tighten the wires at all. I'm so pleased that I found this product!
Good quality and work well. They are very pricey if you need to do a large area.
For the first one I used a cordless drill to tighten the bolt and the metal is very soft so instantly shredded the screw head. However, as long as you tighten carefully by hand using a normal screwdriver they are fine.