al Underwear: Thinnest
Liang Rou Cotton & Modal Thermal Underwear: Thin
Liang Rou Ultra Soft Fleeced Thermal Underwear: Thick
Liang Rou Thick Fleeced Thermal Underwear: Thickest

Please according to the size information and choose the suitable size
XS/S Size: Chest Measurement 31-42 inch, Sleeve Length 19.5 inch. Pants Length 35 inch, Elastic Cord Waist 22-32 inch. (Recommend for US size 2 4 6)
Medium Size: Chest Measurement 33-46 inch, Sleeve Length 20.5 inch. Pants Length 35.5 inch, Elastic Cord Waist 24-34 inch. (Recommend for US size 8 10)
Large Size: Chest Measurement 35-50 inch, Sleeve Length 21.5 inch. Pants Length 36 inch, Elastic Cord Waist 26-36 inch. (Recommend for US size 12 14)
X-Large Size: Chest Measurement 37-54 inch, Sleeve Length 22.5 inch. Pants Length 36.5 inch, Elastic Cord Waist 28-38 inch. (Recommend for US size 16 18)
XX-Large Size: Chest Measurement 39-58 inch, Sleeve Length 22.5 inch. Pants Length 36.5 inch, Elastic Cord Waist 30-40 inch. (Recommend for US size 20 22)

Liang Rou Ultrathin Modal Underwear Series are high elastic and skinny thin undergarment, and they may become a bit bigger after several times water washing.

36:T782,These feel really smooth against your skin, and help keep you warm when worn as an underlayer, without being bulky or uncomfortable. They are quite stretchy, and XS - S fits me nicely, although it could have been a bit tighter. I am quite short at 5" and take an 8 in casual trousers and normally take a 10 - 12 in tops, because I have quite broad shoulders, but the top also fits me well and is not tight at all. I think XS - S would easily fit a size 10, and the bottoms would be ok for someone a bit taller, but if you're taller than 5"3, I'd guess the bottoms will start to be too short. They easily come down to my ankles without being stretched out properly, so think they'd be ok for another 3 inches of height at least. They're made from 90% modal cotton and 5% spandex - am not sure what exactly