Duty-ready comfort, built for the long haul. The Sinatra Undervest Long Sleeve Base Shirt combines the functionality of a patrol uniform with the comfort of a true base layer — engineered for all-day wear under external carriers with advanced moisture management, breathable construction, and durable materials that keep you cool, dry, and professional through every shift. The lightweight upper fabric provides breathability, moisture management, durability, comfortable stretch, and shape retention.