Upgrade kit for IBM 5155 or 5160 "64-256K" motherboards that brings them up to 640K. If you have a 256-640K motherboard, you only need the DRAM ICs, not the 74LS158 or jumper. To install this upgrade, you must be able to solder the included 2-pin jumper into position E2 above the ROMs.
eBay