Copy on both sides (duplex) - HP LaserJet Pro MFP M521 series
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HP Laserjet Pro M521dn MFP Remanufactured + Warranty ⚫️ 250 Pages⚫️ A8P79A 887111015891 | eBay
New Original For Hp Laserjet Enterprise 500 Mfp M525dn M521 Rm1-8508-000 Rm1-8508 Rm1-8509-000 Rm1-8509 Fuser Assembly - Printer Parts - AliExpress
Clear jams in the duplexer - HP LaserJet Pro MFP M521 series
RM1-6279 HP CASSETTE TRAY STANDARD 500 SHEET FOR LASERJET P3015/M525/M521 SERIES-ImageSpareParts.com
HP LaserJet Pro MFP M521 - Clear jams | HP® Customer Support