A PA rating is obtained via a Japanese testing protocol to measure the protection against UVA rays (the aging rays). In the U.S., as per FDA regulation, sunscreens simply state if they offer protection from UVA rays (via a Broad Spectrum claim) but it doesn't indicate exactly what level of UVA protection that is. Until recently, PA +++ was the highest UVA protection rating but an update to the protocol now allows for PA ++++. Any Supergoop! products that have a PA rating will be visible on the packaging next to the SPF number.
PA ++++ products: Everyday Sunscreen