The sash is a symbolic form of the monk's robe, and as lay Buddhists of Rissho Kosei-kai, we wear it during Buddhist practices such as sutra recitation.  It is available in three sizes. 
 
The product image shows one sash: front view and back view. Sash size measurement is length-wise. When sash is worn, the sash will go over your left shoulder, across your body, down to the right side of your waist.  The size length is this measurement.