These are steel, imperial tail piece posts, suitable for Gibson and guitars using similar tail pieces with 5/16 inch threads

Locking tail piece posts are quite clever actually. The "top" section of the post unscrews onto the bottom, so its capable of "holding" the tail piece in situ, so it will never fall off and go missing mid string change.

Please be aware - this is for 1 (one) post (not a pair)

Thread Spec
Length - 19.8374mm (0.781")
Thread - 5/16" - 24 UNC
Top section of post
Length - 14.4mm (5.4mm top, 1.3mm bottom, central section 6.5mm (when closed))
Diameter - 12mm Top and bottom section, 7.6mm middle section
Material - Steel
Weight - 14g