Well my wife got me the Korilla wavemaker with Korilla 3s for christmas. I looked at the boxes and it said Korilla 3 so I put them in the tank. I was not super impressed with the pumps, but they were nice. Today I working on my tank and realized that the 3s have the same impellor as the old 2s. Then the dim light in my head lit up bright and I looked at the sticker on the pumps. Korilla 2s!! :swear: I about blew a gasket!! I went and tracked down the box they came in and yes they say 3s. Anyways I called Dr fosters and they are going to get ahold of Hydor and get me the right pumps so now I sit and wait. The moral of the story, check the pumps and not the boxes or you could end up with a nano instead of a 4 (I know, there is a big difference between the two). Too bad I didn't end up with 4s instead of 2s, but thats my luck.