Memory water blocks serve to cool the system memory (RAM) in your custom PC.  They typically come in two parts: the water block itself and heat sinks for the memory modules that attach to the block.  These are sold separately so be sure to get everything you need to cool your PC’s memory.

TITAN RIG has memory water blocks made to fit either two memory modules or four and come with tops made of materials like acetal and acrylic.  Some even have RGB LED options.