Apple 661-7510 | 4GB DDR3-1600MHz PC3-12800 non-ECC Unbuffered CL11 204-Pin SO-DIMM 1.35V Low Voltage Memory Module for iMac 21.5

Here are the technical specs for the Apple 4GB DDR3-1600MHz Memory Module:

- Memory Type: DDR3 SDRAM
- Memory Speed: 1600 MHz
- Memory Size: 4 GB
- Memory Standard: PC3-12800
- Error Checking: Non-ECC
- Signal Processing: Unbuffered
- CAS Latency: CL11
- Pin Count: 204
- Form Factor: SoDIMM
- Voltage: 1.35V

Helpful notes:
- This memory module is specifically designed for iMac 21.5 models.
- The low voltage of 1.35V helps to reduce power consumption and heat generation.
- Non-ECC memory is suitable for most consumer applications but may not be suitable for mission-critical systems.