SanSoleil "SolCool Fabric" Fitted Zip Mock offers moisture-wicking, quick-dry, and cooling ventilation. And, most importantly, UPF 50 Protection. SanSoleil's Zip Mock Collar Stand adds extra protection for the back of the neck, while SanSoleil's UV 50 enhanced fabrics provide UV 50+ protection. (Normal fabrics offer much less protection from the sun.) SanSoleil's Sleeveless Tops are great for sports that require fabrics that move and are lightweight for exertion in the sun's heat. 
 
UV 50 Protection: SolCool Offers Permanent UPF 50 Sun Protection. Never washes out. (Many 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.)
Easy Care: SolCool is light with Athletic Stretch, yet can be washed and dried in regular cycle.
Great for: Golf, Equestrian, Tennis, Sailing, Walking, Hiking, Boating, Fly Fishing
SanSoleil's Exclusive Prints: SanSoleil's Team of Artists Create the Finest print for Sport!
 
SIZING Guide
BUST (INCHES): XS/ 32-34, S/ 34-36, M/ 36-38, L/ 38-41, XL/ 41-44, XXL/ 44-47. 
(HOW TO MEASURE BUST. With arms relaxed at side, measure the fullest part of the bust/ chest, about 1" below armpit, keeping tape parallel to the floor.)