Most if these sound like they have enough pressure for quite a lot of tubing - if specs believable. Also, as my figures hopefully showed, you don't need much flow if water mixes fully. 42 watts per (cc per second) at 10C rise. Long tubes allow you to add unreliability and risk of coolant loss and death of cpu which adds spice to life :-) >From page of pump which Electron recommended. http://images17.newegg.com/is/image/newegg/35-108-063-S02?$S640W$ http://images17.newegg.com/is/image/newegg/35-108-063-S06?$S640W$ 22 psi 60 C max temp. Noryl material (glass filled nylon afair). Russell --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .