Kingston KVR667D8P5K2/4G | 4GB Kit (2 X 2GB) DDR2-667MHz PC2-5300 ECC Registered CL5 240-Pin DIMM Dual Rank x8 Memory

1. Memory Type: DDR2 SDRAM
2. Memory Size: 4 GB (2 x 2 GB)
3. Memory Speed: 667 MHz
4. Memory Standard: PC2-5300
5. Error Correction Code (ECC): ECC Registered
6. CAS Latency: CL5
7. Pin Count: 240-pin
8. Rank: Dual Rank x8
9. Voltage: 1.8 V
10. Module Configuration: 256 x 72
11. Form Factor: DIMM
12. Compatibility: Designed for use with server and workstation motherboards

Notes:
1. ECC registered memory is more reliable than non-ECC memory, making it ideal for use in servers and workstations.
2. Dual rank memory modules provide better performance than single rank modules.
3. Ensure compatibility with your motherboard before purchasing.