Yes there is such a thing now. Coons were getting to my gravity feeder and would empty 200# of golden nuggets in about 5-7 days. We tried to deter them with not much luck until now. First we put flashing on the post to cover about 48" at the bottom. It worked for a couple days until they figured out to put their front feet on the back of the post and back feet on the front. Thus would shimmy up the pole, out the arm, down the cable and onto the feeder.
...
Braydon and I then attached "sharks teeth" to the top of the flashing. They gained a little blood and hair but did little to save the feed. Then I came up with another idea. We took a black plastic 55 gallon drum and cut the bottom off to about 15". We then cut a square out in the middle of the bottom to match our 4"x4" post. We then split the drum up the side and across to the center square. I nailed 4-2x4's onto the post to stick out each direction for support 
(I'm no artist, but attached them in this pattern). Then the drum was fed onto the post and screwed in place. The split in the drum was fastened back together with metal straps and bolts. (Sharks Teeth are up inside the drum). Now when the coons get up inside the drum, they are at a dead end and nothing but the sharks teeth to keep them company. 
I have kept an eye on this feeder for 2 weeks now and the feed is still fine except for what the deer have taken. I washed the feeder down with water and no coon prints have showed as of yet!
... Braydon and I then attached "sharks teeth" to the top of the flashing. They gained a little blood and hair but did little to save the feed. Then I came up with another idea. We took a black plastic 55 gallon drum and cut the bottom off to about 15". We then cut a square out in the middle of the bottom to match our 4"x4" post. We then split the drum up the side and across to the center square. I nailed 4-2x4's onto the post to stick out each direction for support (I'm no artist, but attached them in this pattern). Then the drum was fed onto the post and screwed in place. The split in the drum was fastened back together with metal straps and bolts. (Sharks Teeth are up inside the drum). Now when the coons get up inside the drum, they are at a dead end and nothing but the sharks teeth to keep them company. I have kept an eye on this feeder for 2 weeks now and the feed is still fine except for what the deer have taken. I washed the feeder down with water and no coon prints have showed as of yet!
