ALL ABOUT SYLVANIA SARONG CATHODE COATINGS

In 1959, Sylvania made much of their new technology cathode coating process which they termed 'Sarong'.    The coating was characterised by an enhanced surface smoothness which to a certain extent was a 'Sword of Damocles'

On the one hand, the smoothness of coating would lessen the effect of localised 'hot spots' - not much of a problem with the small signal valves shown in contemporary literature.  Conversely, there would be a reduction in surface area that could lower emission and cathode life.   As you can see, you pays your money and makes your choice.

A sarong or sarung (/səˈrɒŋ/); is a large tube or length of fabric, often wrapped around the waist, worn in areas of Southern Asia.   The term sarong is an English loanword of Malay origin meaning 'to cover' or 'to sheath', first used in 1834 referring to the skirt-like garment of the Malay.

I suppose the alternative terms Sheath or even Condom were considered by Sylvania's marketing team - and summarily dismissed at the time!!!!!!