Stretchy malas that are made to fit on the wrist and thus may not have 27 beads or some other multiple of 108 beads. The number of beads on a stretchy (or adjustable) mala varies.
Although stretchy wrist malas may vary in their number of beads, they may still be used for mantra practice. Wearing a stretchy mala is especially convenient for a person who is ill and would like to recite mantra in bed; the stretchy wrist mala is always right there on their wrist. Today people often wear stretchy malas as a reminder to be mindful.