They came loaded on my Human Base 4 string, medium gauge, but I'm replacing them with DR Sunbeams, cos that's my jam. I'm looking for like, $5 bucks plus actual shipping (so probably like $9 total). These were on a bass with 2+2 arrangement, so I doubt they will fit Fender headstocks, but any 2+2 should work. Great deal for new strings! PM me! Would also trade all four for ONE DR Sunbeam G-string (.45 gauge).