
I have two types of split ring markers, one type (white in the photo) that I really like but haven't been able to find anymore.
The small white, split ring markers are very useful when knitting and marking fingering and sport weight yarns and when using small diameter needles.
The green and orange markers are better for larger diameter yarns or when you want to hold a few stitches at the end of the row for completion later. Clover sells the green and orange markers as Locking Stitch Markers (#353).