SanSoleil’s newest most advanced cooling fabric SolTek LUX combines Super Cool Nylon with SanSoleil’s mesh inserts and quick cool technology to create the perfect fabric for golf, tennis, and sports! *Garments with SanSoleil’s SolTek LUX fabric run one half to smaller than other SanSoleil garments. SolTek LUX has enhanced stretch for a more athletic fit. Please size up if you question the size you should wear.