A CRYOGENICALLY FROZEN LIGATURE FROM LIGATURE SPECIALISTS SILVERSTEIN Cryogenically treated metal allows for uniform and maximum resonance throughout the range of your instrument. In order to create this sound Silverstein have developed a special alloy known as SLA23. Five cords and four fine tuners offer a full free-blowing and agile response, with just the right amount of resistance and focus to maintain a centered and strong projection.