The new IQ Pack incorporates the "soft/hard" concept (the optional back plate slides in behind the back pad), form fit, easy on/off has been re-engineered to provide a more streamline appearance and fit. There are now (2) butt mounted D-Rings, (3) D-Rings per side, (1) adjustable D-Ring on each side of the harness chest area (additional optional D-Rings can be added) and (2) D-Rings located at the oblique (waist) area. Additionally, an optional single cylinder Cam Band system has been integrated into the back of the IQ Allowing for very lightweight travel. The OMS IQ Pak is without question the hard-core tech diver&';s first choice! This BCD is an incredibly rugged back mounted weight integrated modular system that offers you an incredible variety of choices to fit your precise diving needs. Choose from 45lb, single 100lb, or dual 100lb bladders. Pick between Aluminum or Stainless Steel Back plate. Soft/Hard" Concept Streamline and Better Fit 9 D-Rings Incredibly Rugged Fits 45,100 or Dual 100lb Bladders Fits All OMS Back Plates Sizing XS/SM - Waist: 32"-46", Height: 5&';2"-5&';9", Weight: 150lbs-180lbs, chest: 36"-40" MD/LG - Waist: 34"-48", Height: 5&';9"-6&';4", Weight: 185lbs-240lbs, chest: 40"-50" LG/XL - Waist: 40"-54", Height: 6&';4"-7&';0", Weight: 220lbs-300lbs, chest: 48"-60"