First we reviewed the WCL-02 120Cu and now we have a go at the new WCL-02 90Cu. Don't let the numbers confuse you into thinking these are similar units, because they are entirely different. The WCL-02 90Cu arrives completely assembled and is ready to be installed in your system as soon as you attach the water block to the the processor. No need to fill it, drain it or even burb the lines. We tried it on two different machines just to see how well it would work under normal operating conditions and then on a second machine with a 500 MHz overclock. So check it out.