This is a single Tesla EL84 (6BQ5) vacuum tube. It was made in the Czeck Republic and was in a Ruby tube box so I assume it was branded as a Ruby tube. It was part of a matched set rated as PC 26, TC 6350 and tested strong with no grid leakage or shorts. See attached photos. Shipping is to the lower 48 states via USPS and are also available for international shipping using eBay's global shipping program.