(!) 12AT7WA Raytheon NOS black plates - triple mica - O getter halo 1960's mis-matched triode sections (7/12ma)1 low noise tube) 12AT7WA Raytheon NOS black plates triple mica O getter halo 1960's mis matched triode sections in white box 7ma Gm=4000 12ma Gm=5300 Recommended for Eclair Engineering 'Evil Twin' Tube DI (direct input box) Atma sphere preamp JC Morrison custom phono David Berning Quadrature Z amp