Bought because 25 from a big box is ridiculously expensive. I can't justify spending 5 slides more than the rest of my project! For unknown reasons, 2 ball bearings fell out of one. Otherwise 5 stars! With a little Wd40 etc. it's oil! As with any fastener, measure 50 times and install once. A user error has brought me a lot of sweat and tears. But luckily they have as many holes as me. The project is not lost!