The 7586 Nuvistor type, manufactured by Philips in USA. RCA introduced the Nuvistor in 1959  as a miniature, rugged, metal-ceramic enclosed vacuum tubes, as a serious competition for the transistor. The 'Nuvistor' name evoke similarities to the words 'new' and 'transistor'. The 7586 is a medium mu triode. The Nuvistor was the final evolution of the thermionic valve as a general purpose active circuit element. 
Manufactured by Philips
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