Oh, I know how they work - we have an ET-8550. I just didn’t realise generic ink could be so cheap. My wife sells prints of her photographs and artwork so is a bit “cautious” about her ink and only uses genuine Epson at $25 per 70ml. I just looked on Amazon and found that generic ink can be had for around $6-7 per 70ml ($40 for a 6-pack) - wow!