HP Q2628A 512MB 100pin DDR SDRAM DIMM for HP LaserJet 4250 4250n 4250tn 4250dtn 4250dtnsl 4345 4345x 4345xs 4345xm Printer Memory 512MB 100pin DDR printer memory upgrade Part#: Q2628A, Q7720A 100% Compatible with Lifetime Warranty Manufactured by Keystron, LLC Keystron is a registered trademark of Keystron, LLC