Posture  Trainer
XS - M Professional Power (for hard workout)
L-XL Professional Power (for a bit easier workout)

XS-M Medium Power (for easy workout)
L-XL Medium Power (for easiest workout)

Position / Stabilize (Waist measurement in centimeter)
XS 60-75 cm, US 23”-25”
S 75-85 cm, US 26”-32”
M 85-95 cm, US 33”-38”
L 95-120 cm, US 39”-44”