Large lead nuts (7/8" wrench size) with brass thread inserts and 5/16" coarse thread. Were used in solar energy lead-acid battery system, and were greased and have acid residue (though impervious to acid damage). The box has at least 90 uncleaned nuts in it and weighs about 15 pounds. Nearly all look just like the one up front and will clean up just like it. They have excellent threads.
Also available (negotiable) are the brass rods that threaded into the nuts and connected the battery terminals. Call or email Tom (landline, no texts)