The "kryographics Hawaii for Radeon R9 290X and 290 acrylic glass edition" blocks are not compatible anymore with the OLD "AQUACOMPUTER TWIN CONNECT 1-2 SLOT!" offered in your link. These new water blocks have bigger flow optimised in- and outlets, therefore you need the "kryoconnect kit for kryographics". In your case you'll need somethink like the kryoconnect kit for kryographics with active back plates, width 3 slots for 2 graphics cards I think. But I'm not 100% sure if it's the right one in your case.

kryoconnect kit for kryographics with active back plates, width 3 slots for 2 graphics cards


twinConnect kit for GTX 680/590/580/570/480/470/460 and HD 7970/7950/6970/6870, 1-2 slot distance