Looking for a shirt that will keep you cool and comfortable all day long? Look no further than the Blue Whale 155g Hi Vis Long Sleeve Day Night Drill Shirts. Made from fine quality cotton twill, this shirt is pre-shrunk and features underarm air flow vents to keep you cool and comfortable. The hidden back shoulder vent provides even more airflow, while the twin pockets with button-up flaps offer plenty of storage space. Class D/N, these shirts are perfect for day or night use. And with a UPF rating of 50+, you'll be protected from the sun's harmful rays.