https://www.guru3d.com/news-story/ek-momentum-rog-strix-z390-i-monoblock-for-the-mini-itx-rog-motherboard.html
 
EK Water Blocks, premium computer liquid cooling gear manufacturer from Europe, is releasing an Intel LGA1151 socket based monoblock belonging to the Quantum Line. The EK-Momentum Strix Z390-I is tailor-made for the ROG Strix Z390-I motherboard. The mini-ITX form factor often suffers worse airflow due to less space, and having less space on the motherboard means less VRM components can be built into it.

Having liquid cooling over the VRM area in mini-ITX enclosures is extremely beneficial for the motherboard lifespan and ability to get high overclocks. The addressable, digital RGB LED in the monoblock is compatible with ASUS AURA RGB control, thus offering a full lighting customization experience for every single diode at any given time.
 
Availability and Pricing
EK-Momentum ROG Strix Z390-I D-RGB - Plexi monoblock is made in Slovenia, Europe and is readily available for purchase through the EK Webshop and Partner Reseller Network for €141.90.
 
I think that is a fair and reasonable price and I also like the RGB.