Is the pharma Magica protecting the equipment of the Magus if he carries it at the Moment he activates the pharma. About clothes and jewelry I would tend to say yes. But things found shortly before the next activation? A magus may have found a letter that proves his main rival broke the Code. The bad magus wants to destroy this letter on the next day. Will it be protected by the good magus Pharma
I don't have my books with me right now, but I'm pretty sure that is addressed in the definition of Parma Magica in the main sourcebook. I kinda recall something to the effect that it protects anything really close to the magus' body, like clothing, more or less like the parma extended just an inch or so out of the body. So regarding the letter, I would say it would not be protected, unless the magus somehow "glued" it to his chest or something like that.
A magus's Parma Magica covers clothes and things very close to him (ArM5, page 85). If he has a pouch with the letter in it, that might be outside the Parma's range (varies by saga, as it's not clearly defined; I personally would count that as within its range, though) but if the magus has the letter tucked away under in their robe or somesuch, it would definitely be protected.