FIVE12 "I'm On Vacation" Running Singlet: Men’s and Women’s Running Singlets are designed to have a relaxed running fit, and moisture management advantages, with 1-2” of ease. Made of advanced VOmax MicroDry fabric for maximum breathability and featuring a UPF sun protection rating of 30. The fabric has horizontal stretch allowing it to fit next to and move with the body in motion. If you prefer a looser fitting top it is recommended that you size up.