SanSoleil 900463 Solcool Print Mock -Stars & StripesUV 50 Protection: SolTec Offers Permanent UPF 50 Sun Protection. Never washes out. (Most other polo shirts only offer UPF 10 and use a topical "plastic spray" to produce their sun protection. This washes out after a few washes.) Permanent Cooling: SolTec wicking and quick dry create a cooling effect that provides perfect comfort while protecting from the sun Mesh Venting: Mesh inserts sewn ito sleeves create a billowing effect while walking. Keeping