The Inversion Crew (Midweight) base layer is a premier flame-resistant garment with an advanced tri-blend yarn system that provides unparalleled performance across mild to cool environments. Inversion is inherently sweat-wicking and is designed to create a quick-drying and breathable garment, and the inclusion of spandex gives the end user an improved range of motion, superior comfort, and extraordinary recovery for after-wash durability. Safe-to-Fly (StF) Approved by U.S. Air Force - Air National Guard.