bytom was surpose to be an asic only coin but gpus attacked bytom and made those early asics obsolete.
early weak asics bitmain shipped to their customers ehhe, the real powerful bytom asics are used for mining up to this day at bitmains warehouse hehe, f3 for eth is one of them, 10 times more powerful than the e3. Powerful asics are never shipped to customers, all in house.