Tube measures 35mm in length and is approximately 2.7mm thick with two loop on the top 27mm apart (use these loops to attach to the clasps etc). There is a little 'arm' at each end, which is folded down to keep the beads inside the tube. Fold the arm down on one end first, then gently wiggle and slide the beaded piece through the tube. Then fold the second arm down. You can then finish off by hanging the piece from a necklace, or attach to a clasp via jumprings, for a bracelet. The tubes work on size 11/0 Japanese seed beads only, and usually only on square stitch, or work that has beads in a straight line on the end rows (definitely not peyote). These tubes give the nicest, neatest finish you can believe! Where have these been all these years!!??