UPF stands for ultraviolet protection factor – think of it as SPF for clothing. It tells you how much UV radiation comes through a piece of fabric.
A UPF 50+ fabric blocks 98% of UVA and UVB rays, a UPF 5 fabric (most white cotton t-shirts) blocks about 20% of UVA and UVB rays. All Joju products are UPF 50+.
There are two ways to create sun protection in clothing: Materials & construction of a fabric or a treatment applied after the shirt is made.
Joju products get their UPF protection from their materials & construction. We use naturally sun protective fibers like nylon, polyester and spandex and weave them together tightly to minimize UV transmission. Joju’s sun protection is built into our fabrics – it cannot be washed out.