Gold Paw Sun Shield Tee is silky soft, lightweight stretch jersey with a UPF-50 rating that blocks 98% of the sun’s harmful UV rays. It is not a chemical treatment - it's a mechanical quality of the yarn so the protection won't diminish with washing. Super comfortable indoors and out and perfect for all sorts of applications beyond sun protection too: skin conditions, wound care, topical medications, works great as an anti-anxiety calming aid that can be worn all day.