Normally I am a perfect ""M"", but as I am long distance swimmer with broad shoulders, I followed the size chart and opted for a ""L"". Shoulders and chest fit are absolutely perfect, although body is a bit on the long side. Good for tucking into trousers. Pictures on website also show this, therefore worn as an undergarment it is great. Ribbed cotton fabric and binding are exactly as depicted. Square chest cut accentuates shoulders and pecs. Cotton is lightweight, soft and conforming, without being bulky. Easy wash and wear and workmanship/tailoring is top-notch! Probably the best available and product is highly recommendable. Will most definitely purchase more.