Umbrella test UPF and UVA index
Umbrella test UPF and UVA index Umbrella Test: On the label of the umbrella, there are two important indexes. One is UPF (UV protection factor value) and the other is UVA (long-wave UV transmittance). According to the National Standard for National Umbrella, the UPF value must be greater than 40, while the UVA should be …