This is a great product and excellent for the price. If you are just needing rails this works for simple heavy-duty guidance. If you are building robotics, I would recommend the slim square rails with ballscrew. As the main alum, I had the hardest time designing parts for this rail system. barrings are very thick and wide off the build plate. There is a use for everything and for the time these worked very well. For the right project, I'd recommend.