Zalman ReseratorXTBlack Hybrid Cooling System (Black) Reserator XT combines active cooling with passive to accommodate the needs of those who seek ultimate cooling performance without giving up silence. High Performance hybrid Cooling System (Natural air convention incorporated w/ forced convection by a blow-in 140mm fan). Switchable between automatic and manual control modes along with an alarm system for any abnormalities with the water flow rate / Flow Level of the liquid.