I`m trying to buy some clothes online from Ebay, mainly shirts. In my region (South America) my Neck Size is 41/42. I`ve recently bought a couple of shirts in NYC and they are 16.5 36/37 and it`s a bit large. I`ve been watching one but says Neck Size 16.5 32/33 and just wanted to know the difference. Maybe a dumb question but I`ve no idea and wanna double check first before buying. Thanks.