Jack sent me a PM to remind/ask me to describe the linked markers I use. These aren't my invention, but I'll pass the info on to you.
As you can see from the attached photo I make them with split rings
. I either just use my thumbs or a pliers..whatever is handy. Once I make them I tend to keep them as they are and if I need a different number I make a new one. I put beads on the bottom so I know which is the top.
These come in really handy for something that you don't do every row, but you want to be done on a specific row. Like cabling for instance - if you want to twist the cable every 6 rows you'd use a 6 ring marker. I place the marker in a few stitches on the row so it won't fall off. I have also placed it on the previous row at the end (1 stitch in).
Each time you come to the marker you pick up the next loop with your right right needle and keep on knitting. If it's the loop with the bead you know it's time to do the cable cross (or whatever).
I've actually got a linked marker that I'm using right now that is long and has a bead at the end and another midway down because I'm doing two different things that require two different number of stitches. It's a little trickier to use, but I've done this enough it's pretty easy.