Belt of Warding
This is a belt. Like, the clothing item. Made of a soft, suede-like material that is vegan, and not plastic or synthetic. It’s magic. It will never wear out, no matter how much it is worn. The color, pattern, and dimensions of the belt can be altered by the wearer as desired. You just will it to change its appearance; you can do this as much as you want.
When the belt is worn on the torso (over or under clothing, or just by itself), the wearer is protected by a magical field. The field is invisible and has no physical form. Harmful bacteria cannot penetrate the magical field. Neither can toxins of any kind, or mold, or any dangerous substance, or gas, or anything that would be harmful to the wearer. It also acts as a sunscreen; you will never get sunburned while wearing it.
The magical field does not interfere with normal activities in any way; the wearer can do anything they would normally do. Eating, going to the bathroom, swimming, sex (and it is protection against STIs), vomiting, whatever. The magical field doesn’t interfere with anything that it shouldn’t; it just keeps the wearer safe.
The belt should be washed occasionally; You can just throw it in with the laundry. If you don’t wash it, the protection will start to become less effective. How long it takes to degrade depends on how often it is worn. But if you wash it, it returns to full effectiveness, no matter how “dirty” it was.