I think these are solid brass, but I’m not guaranteeing them to be. A horseshoe magnet 🧲I have that is strong will not attract in the slightest to these. These are nicely threaded and accept an 8/32 screw. A number 8 with 32 threads per square inch fit perfectly and smoothly in their threads. I will ship USPS Ground Advantage, as soon as the item is paid for. Thanks, for looking, please view my other listings!