We absolutely love the copper portal protectors. The 1" size protects our wren houses from invasion by larger birds and prevents squirrels from chewing and enlarging the entry holes. We've also used these protectors to secure the metal grommet openings in our woodpecker feeders, thwarting the squirrels' attempts to pry the grommets out to get to the peanuts. The copper weathers to an attractive verdigris in time. Thanks for a great product!