You may be confusing with 3rd edition a specialist wizard can cast spells from his opposition schools they just occupy 2 slots instead of 1. Therefore they are on his spell list and he can use wands,staves and scrolls (spell completion items) as normal. (Unless he is a Thassilonean Specialist).
Also a constant effect item like a ring of water walking works for anyone regardless of their ability to cast spells they work for fighters, druids wizards and commoners.
I don't do page references , that takes time and you can read you won books for them
Thanks for the answer I guess, though I'm sorry for inconveniencing you. And while I did read Wizard section of the Core Book I thought there was another section from the Core Book (or maybe another book) that had didn't let specialist wizards use magic items from opposition schools, or maybe it was more difficult for them to use them.
And I like to get page numbers listed so I can 1) find the reference, which I obviously wasn't able to do, and 2) read it myself. It helps keep people from miss-remembering rules or misinterpreting rules.
Again, sorry to trouble you for help.