2pcs 38mm Tube Dampers Silicone O-Ring Fit 2A3/300B/5Z3P/6L6G Audio Vaccum Advising:4pcs for each tube; Inisde Diameter:38mm; Coil Diameter:4mm Package Included:  2pcs 38mm Tube Dampers Silicone O-Ring Fit 2A3/300B/5Z3P/6L6G Audio Vaccum