The Mahi "Side To" side vented fishing shirt from Tormentor is made of KNITTED Polyester/Spandex which is the original and true performing fabric. Most others have now gone to 100% Polyester WOVEN which is Cheaper and does not wick nor breathe the way our fabric does! They have gone to the WOVEN Poly fabric as it will not snag, but it will not breathe either! Our KNITTED fabric is SNAG PROOF so we did not need to switch as the others have. In addition to being breathable and moisture-wicking, this shirt is also fast drying and so you can wear it while fishing, surfing or any other water sport. The side venting is printed with authentic Mahi skin artwork. On the sleeve, Tormentor is printed with in the same Mahi skin.