It is not so EH2 related but i also own a water cooled amplifier.
Its from an old Coherent DEOS Lasersystem, delivers easily 1,2KW on VHF.
Supply voltage is 48V so not usable as "portable" amp, not to forget the needed chiller.
1K2 looks much on VHF but compared to the bigger Laser RFPSUs (E1000) with >10KW at my QRL this is a tiny amp
I only fired it up once on a dummy load, because neither my coaxcable or antenna can handle this much power.