ML - Flat 2, max stretch 2.4 chi waistXL - Flat 2.4, max stretch 3.0 chi2XL - Flat 3.1, max 3.5 chi waist3XL - Flat 3.6, max 4.2 chi waist4XL - Flat 4, max stretch 4.4 chi5XL - Flat 4.4, max stretch 4.8 chi6XL - Flat 4.8, max stretch 5.2 chi7X (300-350 lbs approx.)8X9X