Keystron (OKI P/N 70061901) 512MB DDR2 144Pin Memory RAM for OKI Color Printer C711n, C711dn, C711dtn, C711wt, c831, C831dn, C841, C841n, C841dn 512MB OKI printer memory upgrade Part#: 70061901 100% Compatible with Lifetime Warranty Manufactured by Keystron, LLC Keystron is a registered trademark of Keystron, LLC