Icebreaker Size Chart An ultra-comfy underwear bottom for everyday wear. The Siren Hipkini is made from Icebreaker's ultra-lightweight merino wool jersey with a touch of LYCRA(R) for stretch. Features: - Updated fabric - Corespun fabric for enhanced durability - Naturally odor-resistant - No-itch comfort - Regulates body temperature - LYCRA(R) content for stretch and mobility - Low profile elastic waist and leg opening - Low profile side seams for comfort - Icebreaker tonal screen print logo - Medium = 34 g / 1.19 oz - 83% Merino Wool, 12% Nylon, 5% LYCRA(R)