Help with Crucial Memory purchase

[i might imac]

I go to Crucial.com and I don't see my computer in the drop down box unless it is this one they mean;
Apple iMac (Retina 5K, 27-inch, 2017) iMac18,3.

What makes me pause is the 18,3 part of it. I don't know what this means and don't rememberever seeing it in specs of my purchase.

By the way here is what I bought;


27-inch iMac with Retina 5K display
With the following configuration:
4.2GHz quad-core 7th-generation Intel Core i7 processor, Turbo Boost up to 4.5GHz
16GB 2400MHz DDR4
1TB SSD
Radeon Pro 580 with 8GB video memory

Is this the correct RAM module for this computer.

Crucial 16GB DDR4-2400 SODIMM Memory for Mac

• Upgrade for: Apple iMac (Retina 5K, 27-inch, 2017) iMac18,3

• Crucial part number: CT10559857

• Brand: Crucial

• Form Factor: SODIMM

• Total Capacity: 16GB

• Warranty: Limited Lifetime

• Specs: DDR4 PC4-19200 • CL=17 • Dual Ranked • x8 based • Unbuffered • NON-ECC • DDR4-2400 • 1.2V • 2048Meg x 64 • lead free • halogen free • for Mac

• Series: Crucial

view all product details
Product Specifications
Brand Crucial
Form Factor SODIMM
Total Capacity

16GB
Warranty Limited Lifetime
Specs DDR4 PC4-19200 • CL=17 • Dual Ranked • x8 based • Unbuffered • NON-ECC • DDR4-2400 • 1.2V • 2048Meg x 64 • lead free • halogen free • for Mac
Series Crucial
ECC NON-ECC
Speed 2400 MT/S
Voltage 1.2V
DIMM Type Unbuffered

Thanks for any and all help.

 

[SaSaSushi]

18,3 is the model identifier for the 27-inch Late 2017 5k iMac.

See this page for more information.

The RAM you ordered is exactly the correct model for your machine.

 

[Glmnet1]

Yes, that's it. iMac 18,3 is because the June 2017 iMac are the 18th generation, the non-4k 21.5" is the 18,1, the 4k is the 18,2 and the 27" 5k is the 18,3.

Congratulations on your purchase!

 

[i might imac]

Thank you both for the clarification.