Activity for Peter Hahndorfâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Question | — |
What's the UPF of a T-Shirt or jeans? Many outdoor clothing items advertise themselves with a UPF (Ultraviolet protection factor) of 30 or even 50. How does that compare with a normal cotton T-Shirt or a pair of jeans? Do I have to use sunscreen even when using these clothes? Or is it all a marketing scam? (more) |
— | almost 13 years ago |