The Ultimate in-case protection for your octave key and neck receiver! GapCap™ is THE ULTIMATE SAX CARE CAP and won "Outstanding Product" designation from The Saxophonist Magazine. 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. Spring wall design flexes to fit the neck socket of all saxophone brands. Flex spring wall serves as a shock absorber to decrease impact 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. GapCap™ vents through the center and side to allow massive airflow into the saxophone body tube. A proven way to keep the saxophone cleaner and help pads last longer. Ditch your old sax end plug and go with a GapCap™ to flex, expand, vent and protect your saxophone. - Flex wall spring fits the sax perfectly - Shock absorber protects from impact - Vented at top and side to air dry the sax and pads - Expanding end cap to fit any sax case - Octave key protection like nothing else