This was exactly what I needed to secure an area of fence from doggie escape where the fence was not flush with the ground and my little digger can't resist a squirrel on the other side of the fence.  They are not entirely unobtrusive or invisible, but once I fill in the plant beds in that part of the yard you won't be able to see them.  If you just have grass near your fence, you may find it bothersome that you can see them. I used a rubber mallet to pound them into the soil.  I did find that that I could't place hem perfectly symmetrically along my fence sections and had to leave larger gaps near my fence posts due to the concrete in the ground where the posts were sunk.