GORE WEARGOREWEAR M GORE WINDSTOPPER Base Layer Thermo Long Sleeve Shirt

Q: Is the material used under the arms and in the back a light fleece (vs. the mesh used on the non-thermo model)?

It is not mesh. It seems to be a light lined fleece material, not the rigid plastic surface on the front. It allows for heat and moisture to escape while blocking oncoming wind but you won’t get cold from an mesh venting. This is good between a baselayer and and outer layer vest, light jacket or jersey down to about a high of 40 degrees. Might be too much for anything over 50 degrees F.

Q: To keep just wind out and use over a T-shirt or long T-shirt as casual sweater? How many sizes I need to go up for that. Im 40”chest, 73 kg. 174cm.

I wear mine over a thin hydrophobic t shirt. And it keeps heat amd sweat away from my outer layers so you don’t need as much insulation. (In addition to blocking wind ) a lot like a vapor barrier on a house. I wear Patagonia large shirts and vineyard vines medium and am a 33-16 dress shirt slim cut from brooks brothers. I have two of these in size Large. ( But I bought them in2021…and I am fairly certain gorewear changed their sizing ) so my large may be a 2022/23 medium now. Google when they changed the sizing and in which direction. I wear mine down hill skiing on really cold days out east. This shirt is awesome. I wish I bought one with the zip up neck actually.

Q: What size in men's would be equivalent to a ladies xl? i purchased a ladies large and it a bit tight and it does not come xl.

I dont think you can compare a mens to a womens in Gore. Gore contours the ladies wear differently than the mens. Due to the curves of a woman around the chest area. Not saying a mens wouldnt fit,just not be as comfortable as a womens shirt.