UnDShurt Long Sleeve100% Polyester The UnDLite is thin and form fitting, engineered for wearing as the first against the skin base layer. Made in the USA from moisture wicking fast drying fiber. Suitable for temperatures from 40F to 80F. Machine wash cool, tumble dry low. **Measure around the fullest part of the chest, under the arms, and including shoulder blades.** DeFeet SM MD LG XL USA 34 37 in 37 40 in 40 43 in 43 46 in EU 86 94 cm 94 102 cm 102 109 cm 109 117cm