MULLARD ECC81 12AT7 NOS UK MADE Valve. Will often replace ECC83/12AX7
MULLARD 12AT7WA NOS UK MADE Valve Tube. In most cases will replace the hard to find and expensive 12AX7/ECC83. Has slightly lower gain which may not even be noticed. Will be AVO tested for balance between halves and matched in pairs or quads.