B40X1510 512MB 100pin PC2700 Memory Upgrade for Lexmark Printer 920, 935; T640, 642, 644; W840; X644, 646 ReviewbP PP 40X1510 512MB 100pin PC2700 Memory Upgrade for Lexmark Printer 920, 935; T640, 642, 644; W840; X644, 646 PLexmark PN: 40X1510P512MB PC2700 100-pin SodimmPLife-time replacement warrantyPShip within one day after payment or soonerPShip via USPS 1st class (standard) or Priority mail (Expedited)P