OWC 4GB UPGRADE: Consists of a single 4GB DDR4 2666 PC4-21300 CL19 1Rx8 260-pin 1.2V SODIMM Memory RAM Module Upgrade memory module compatible with QNAP model TS-1253DU-RP. 100% COMPLIANT: JEDEC-Standard and ROHS Compliant. Warranty-Safe Upgrade. Designed and Tested to Meet or Exceed all Manufacturer OEM Specs. EASY INSTALLATION: In Most Cases, Installing Memory is an Easy DIY project. Watch our OWC Basic Installation Video for Help. INDUSTRY LEADING: Consumer-friendly Advanced Replacement Program and Limited Lifetime Warranty, which includes Free Tech Support by Other World Computing. Replacement for QNAP part numbers RAM-4GDR4A0-SO-2666, RAM-4GDR4T0-SO-2666 and RAM-4GDR4T1-SO-2666.