There are two options for ring type. Our stainless steel rings have a 9.5mm inner diameter. They are big enough to fit over size 11 needles but not so big that they're uncomfortable to use on smaller knitting.
The other option is a removable black bulb shaped safety pin, which fits best on needles smaller than size 3.
Because they are made of a natural material, the appearance of each stitch marker may vary slightly.