The beads in an Bracelet Mala are either 21x8mm (typical wrist Mala count) or 18x10mm (18 is representative of the 18 Arhats) and will fit most wrists. They are strung on stretch cord by default but you will have the option to switch to a Bar and Toggle clasp or an adjustable Chinese Sliding Knot (for maximum adjustability) if you wish.

(this image is an example- your Mala will be a unique design)