These are the orignial new old stock version of the 6Y6 vacuum tube, some of these were made prior to the 1940s, and all of them were made in the USA.  These tubes are electronically matched, and may be different brands than each other, and may be slightly different in looks and size, but they all have the coke bottle or ST shape.  All the 6Y6 variants, the G, GT, and GA sound slightly different.  These have the most “vintage” sound of all the variants.