Cisco 921 Gigabit Ethernet security router
| SKU | C921-4P |
| WAN interfaces | 2 ports Gigabit Ethernet (GE) |
| LAN interfaces | 4-port GE managed switch |
| Integrated USB 2.0 | Yes |
| Default and maximum DRAM | Default 1 GB |
| Default and maximum flash memory | 2 GB; not upgradable |
| Dimensions (H x W x D) | 1.70 x 9.0 x 9.5 in. (4.32 x 22.86 x 24.13 cm) (includes rubber feet) |