8pcs 19mm Tube Dampers Silicone O-Ring Fit 12AX7/12AU7/12AT7/EL84 Audio Vaccum Advising:4pcs for each tube; Inisde Diameter:19mm; Coil Diameter:4mm Package Included: 8pcs x 19mm Tube Dampers Silicone O-Ring Fit 12AX7/12AU7/12AT7/EL84 Audio Vaccum