This is a booster for YAMAHA saxophones. I purchased and used it about a year and a half ago. 《Product Description》 Gold plate, accentuates the sound's contours, creating a華やかな (vibrant/gorgeous) impression. By attaching it, a moderate resistance is created, and the flow of breath becomes smoother. The sound becomes unified across the entire range, and a rich, voluminous sound quality is obtained. When attaching the Yany BooStar, please be sure to check that there is no strain. The structure of the screw part may differ depending on the saxophone manufacturer and instrument. Special material neck screw Yany BooStar By attaching it, a moderate resistance is created, and the flow of breath becomes smoother. The sound becomes unified across the entire range, and a rich, voluminous sound quality is obtained. Two types of parts, B and C, with different weights, can be joined to the basic screw A. By combining them, the playing feel and sound quality can be further changed. It can be used according to the song or music scene. (Compatible with soprano to baritone)