Cisco 2951 Voice Sec. Bundle, PVDM3-32, UC&SEC Lic,FL-CUBE10 MEMGB= 2GB DRAM (1 DIMM) for Cisco 2951 ISR, Spare MEMGB= 1GB DRAM (1 DIMM) for Cisco 2951 ISR, Spare MEMMB= 512MB DRAM (1 DIMM) for Cisco 2951 ISR, Spare MEMU2.5GB 512MB to 2.5GB DRAM Upgrade (2GB+512MB) for Cisco 2951 ISR MEMU2GB 512MB to 2GB DRAM Upgrade (1 2GB DIMM) for Cisco 2951 ISR MEMU1.5GB 512MB to 1.5GB DRAM Upgrade (1GB+512MB) for Cisco 2951 ISR MEMU1GB 512MB to 1GB DRAM Upgrade (1 1GB DIMM) for Cisco 2951 ISR MEMMB-DEF 512MB DRAM (1 512MB DIMM) for Cisco 2951 ISR (Default) MEMU4GB 512MB to 4GB DRAM Upgrade (2 2GB DIMM) for Cisco 2951 ISR