The ultimate vibrato solution. The BTS-HT combines height adjustability of the adapter posts with the sealed bearing roller assembly BBF has come to be known for. Used with a "Non-Tension Roller" vibrato (such as Bigsby B3 or B30- NOT INCLUDED). When used with a hard tail guitar, we feel this is the absolute best solution for adding a vibrato to a guitar as you'll be able to dial in the EXACT amount of "down tension" for minimum friction. Once vibrato of choice is added to guitar, the adapter posts thread into the holes left behind from the original stop tail string attachment bar. Posts available in METRIC (most guitars other than Gibson) and SAE (Gibson USA guitars).(Guitar and vibrato pictures are for reference only.) https://youtube.com/shorts/v1lA-czgjOI?si=ZXxbW86-GsMTCgtG