Don't risk your saxophone with loose fitting end plugs, end caps?and sax cases. GapCap flexes to fit?your sax perfectly, screw adjusts to fit your case, shock absorbs impact, and vents air through the top and side for a cleaner?saxophone and longer pad life. The spring wall design?flexes to fit the neck socket?of?all saxophone?brands. Plus, the flex spring wall serves as?a?shock absorber?to decrease impacts that can break your sax. Instantly?fix?a loose?fitting?sax case by expanding the GapCap screw, securing?your?horn?to help prevent bent keys, a bent sax body, and costly repair