Using these KnitPro Mindful Collection interchangeable lace needle tips is easy. First, select the cable you like, either swivel or non - swivel. Then, simply screw the 5'' tip (US size 11) onto the cable. When making a functional 16 or 20 needle, remember to use the 4 tips. As for maintenance, keep them in a dry place to prevent rust. And don't force the tips when screwing them onto the cables to avoid damage. Enjoy your knitting with these great tools!