Measure yourself and select a size that reflects aprroximately similar measurements.
If the measurement of chest, waist and hip are different, choose the size that corresponds to the largest measurement.
Chest Circumference: Measure all around your chest at the fullest point.
Waist Circumference: Measure all around your waist at the narrowest point.
Hip Circumference: Measure all around your hips at the widest point.