Genuine HP 950XL Black Twin Pack Ink OfficeJet 8100 8110 8600Compatible Model: OfficeJet 251dw, 276dw, 8100, 8600, 8610, 8620, 8630 Regarding return: Return accept withine 30 days, we will give full refund if the box is never opened and exact same as what we sell. For any opened box return, we will charge 50% restock fee. We can't accept return for ink cartridge is open and used.