Body Weight Chest Minimum Permanent Buoyancy
Small 110-132lbs (50-60kg) 80-90cm (31-35") 9lbs (40N)
Medium 132-154lbs (60-70kg) 90-100cm (35-39") 10lbs (45N)
Large > 154lbs (> 70kg) 100-110cm (39-43") 11lbs (50N) 
X-Large > 154lbs (> 70kg) 110-120cm (43-47") 11lbs (50N)
XX-Large > 154lbs (> 70kg) 120-130cm (47-51") 11lbs (50N)