Cooler Master MasterLiquid ML240L V2 RGB 240mm AiO Liquid CPU Cooler. It is missing a screw, the one that tight the pump to the backplate, is 4 screws, is missing one, usually you can bought the whole set online as well, but you can spend 40 bucks for something that works fine and 10 in replacement than 90 dollars plus taxes and shipment
eBay