for arc ls25 mk 2 .... it runs russian 6h30p’s only, can’t roll tubes
mk 1 was still 6dj8/6922, this was the model changeover to the russian 'supertube' or so they called it
just buy from arc if cost is not a factor
or order from jim mcshane, upscale audio or thetubestore in canada to save some $, all these excellent tube vendors properly test tubes themselves before shipping, you will get good ones