The Ultra-Pure Black Label Classic valve oil was developed as a slightly thicker synthetic oil. The thicker viscosity of the oil is perfect for older instruments with valve larger valve tolerances due to worn piston or rotors. The thicker oil fills the space between the valve and the casing to help restore the valve action. Silky smooth and long lasting, the Black Label Classic synthetic valve oil is especially effective for use on larger low brass instruments such as baritones, euphoniums and tubas.