Minimac Late 2012 Upgrade Memory

Hi

I have a minimac (late 2012) with two memory slots. The information states that they accept a 1600 MHz DDR3 memory module.

I have two memory cards installed with 2GB each, making a total of 4GB memory.

I believe I am able to upgrade these, but am not certain if that is correct and if so, do not know what is a compatible memory card to use.

Can someone advise me please?

I am operating on OS X El Capitan 10.11.6 with a 2.5GHz IntelCore i5 processor.

Thanks very much

Paul