These are bead-style gold-plated PCB test points, also known as test pins or test beads.
They are engineered to provide secure, vibration-resistant contact for testing printed circuit boards (PCBs).
The gold-plated copper probes ensure excellent conductivity and corrosion resistance.
The beads are made from high-temperature resistant ceramic.
They are used to easily hook probes onto important test endpoints on a circuit board.