POM London Crochet Tam Beret Hat: Khaki POM LONDON Handmade Unisex Tam Beret Hat Colour : Khaki Size : One size fits all, stretchable (will fit 22" head up to 25" head) Material : Khaki 100% Acrylic How to measure your size. Using a tape measure, measure the widest part of your head, just above your ears and eyebrows.