This Boot ROM module is the for Cisco 2600XM Series supporting 256-MB DRAM. The SDRAM on the Cisco 2600XM Series can be configured in combinations of 128 MB, 160 MB, 192 MB, and 256 MB using one 128-MB SDRAM DIMM and any combination of 32-MB, 64-MB, or another 128-MB SDRAM.