The NZXT H9 Flow case, which includes the "H9 All white (ATX, mATX, Mini ITX)" model, is designed to accommodate various cooling solutions, including all-in-one (AIO) liquid coolers.

You can fit a 360 mm AIO in the case. Here are the relevant details:
- The H9 Flow case supports up to 360 mm radiators in the front and top mounts, making it compatible with 360 mm AIO liquid coolers.