So what must a user do if they only have locations that support only a single 140mm fans? Simple, run out and pick up a Kraken X40 for yourself. The X40 is the single slot model of the X60. NZXT promises very good thermal numbers from the X40 because of its powerful pump, larger radiator and 140mm fan. I personally can't wait to see how well it holds up again the bigger brother and other AIO coolers on the market.