Choosing a PlumBand Size
The PlumBand® stretch band comes in two sizes. The Regular size is 90" (228 cm) in circumference and we recommend it for people 4'9" (144 cm) or taller. The Small size is 60" (153 cm) in circumference and is best if you’re 4'8" (143 cm) or shorter.
However, everybody (and every body) is different, so if your height is right on the cusp between our two recommendations, you may need to adjust. For example, if you are long waisted, you may want to err on the side of the Small band. But if you have long legs, you should err on the side of the Regular band.
Now having said all that, size should only be an issue for some of the stretches like the Middle Splits and Arabesque. If you will not be doing those stretches often, the smaller band may actually be better for you regardless of your height, as it will be a bit easier to handle.