HP C4782A, LaserJet 8000, 8100, 8150, LaserJet 8500, 8550, A3, A4, B4 HP C4782A. Compatibility: LaserJet 8000, 8100, 8150, LaserJet 8500, 8550. ISO A-series sizes (A0...A9): A3, A4, ISO B-series sizes (B0...B9): B4