PVJapan 4 100% cotton on inside. Outside 95% cotton and 5% spandex. Material is good, feels soft and provides good support around legs and back part to ensure no leaking (while wearing a pad).Sizing wise I ordered 2x too small as the indications and marges given were not as measured. When initial sets arrived and seeing the US and EU sizes I immediately knew which size to order.For reference:3L is : US L / JP 3XL / UK14 / EU 422L is : US M / JP 2XL / UK 12 / EU 40L is : US S-M / JP XL / UK 10 / EU 38