standard values of gm for a small-signal vacuum tube are 1 to ten millisiemens. It is one of the three 'constants' of the vacuum tube, the other two becoming its get μ and plate resistance Rp or Ra. The Van der Bijl https://blog.globalgoodsguru.com/pu-sealants-for-automotive-applications-enhancing-vehicle-performance-affb2479a44a