ABU? It's military lingo for Airman Battle Uniform. And HQ ISSUE® tactical clothing gives you these military-style Hats that are guaranteed dependable for hunting, chores or anything outdoors. Great to keep the sun out of your eyes or help shield against some drizzle. The hats include screen vents for ventilation and have a paracord chin strap to keep the hat in place. The hats can be easily cleaned by machine washing and drying.