I have tried the tacks, they work ,but not very bright, The tape I mentioned above is so bright I thought someone was shining me away from an area, but I knew no one else was there. You can tie a small piece to a limb and see it from both directions. where with the tacks you have to have them on both sides of the tree. Eric ,I have seen the ones you're talking about,and they are probably great , but they would probably rip me off before the week was done.God bless