21PIN printer print head compatible with SX440, TX420W, TX420, TX430W, SX430, SX438, SX445, NX430, SX430W, SX440w, TX430, SX450, and SX445w printers.This is a used part, removed from a functional and previously operated printer.It is intended as a direct replacement for the print head in the listed models. After installation, initial test prints may show gaps or missing lines due to air in the ink pathways.This is typical following replacement.Perform the printer's Print Head Cleaning function via the Maintenance menu.Allow the printer to remain powered on and idle for several hours before retesting.Repeat cleaning if necessary until normal print quality is restored. Before installation, inspect the print head's data contacts for signs of burning, corrosion, or physical damage.secure connection to the printer carriage.Use only ink and cartridges designed for compatibility with the supported printer models. Important Notice: This aftermarket part is unaffiliated with brands.Model mentions indicate fitment only.