Bugs? Off! The Columbia Men's Insect Blocker™ Knit Long Sleeve Shirt features a proprietary bug repelling Insect Blocker™ technology. This long sleeve shirt is a perfect go-to on days both buggy and muggy: Omni-Shade™ provides UPF 30 sun protection and Omni-Wick™ helps you wick moisture quickly and efficiently. Bye bye, bugs. Hello, warm weather.