THEY ARE PRODUCED BY A DIFFERENT SUPPLIER THAN THE 'NON ECO' SERIES. 12 MONTH WARRANTY! Compatible Printers: HP LASERJET 4200DTN, 4200DTNS, 4200DTNSL, 4200N, 4200TN, 4200, 4200 LN, 4250, 4250DTN, 4250DTNSL, 4250N, 4250N, 4250TN, 4300DTN, 4300N, 4300TN, M4345MFP, 4345X MFP, 4345XMFP, 4345XM, 4345XM, 4350DTN, 4350TN, 4350TN.
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