I don't have any myself but a friend on the prairies uses them and they work great. They are made of 4 inch, heavy wall plastic pipe. The rounds are fused together and the uprights are coped and bolted to three of four rounds. Very light weight and durable. They never freeze down because cattle are moving them constantly. Not recommended for bulls. There is a website for a builder in Manitoba, My friend bought a fuser and pipe and built them himself.