We have gone thru many poles, clips, run line and dog line in the last two years, until now. This set has been up and working with no issues. We hang a pull toy on the line for our dog and she tugs and tugs, in he past the pulleys would get wrapped around each other and then eventually make the lines fray or break. This set up has been a game changer. We even bought an extra trolley for the pull toy.