From what I can find online FR 40 is equivalent to a Medium/Large. Please see the measurements in the picture for an accurate size. Oxbow Fjord T-Shirt Polaire fleece top features a cozy mock neck and long sleeves in a versatile solid black. Crafted from soft polyester microfibers, this lightweight yet insulating piece includes subtle brand embroidery on the chest and a signature logo patch on the back shoulder. The slim, athletic fit makes it an ideal base layer for outdoor activities or a comfortable casual staple.