WorkForce ET-4550
The WorkForce ET-4550's ink system is split, and its own spec line says so: "Replacement Ink: 774 Black, 664 Colour: Cyan, Magenta, Yellow." That means a 140 mL pigment black (up to 6,000 pages) plus 70 mL colour bottles (up to 6,500 pages each). The four correct bottles are below — the 664 black is not among them, because it doesn't belong to this printer.
| Bottle | Type | Color | Approx. Yield |
|---|---|---|---|
| Epson T774120 (compatible) | Pigment ink bottle, 140 mL | Black | 6,000 pages |
| Epson T664220 (compatible) | Ink bottle, 70 mL | Cyan | 6,500 pages |
| Epson T664320 (compatible) | Ink bottle, 70 mL | Magenta | 6,500 pages |
| Epson T664420 (compatible) | Ink bottle, 70 mL | Yellow | 6,500 pages |
ET-4550 Ink Bottles — Black 6,000, Colour 6,500, Two Families Epson's ET-4550 page (and its Ink Finder) give the replacement set as "774 Black, 664 Colour (ISO Yield, Epson Methodology — Black: 6,000, Colour: 6,500)", and the box contents match: 2 × 774 Black with two of each 664 colour. Two families, one printer — the colours are shared with the wider 664 range; the black is the bigger pigment bottle from the 774.
The mirror-image trap sits one digit away: the ET-4500 takes a 664 black and no 774 at all. Listings that sell the all-664 set for the ET-4550 are contradicting Epson's own documentation; our page for this model shows only the four correct bottles.
Every bottle listed here carries our lifetime warranty and 1-year free returns.