On eBay - but they're not cheap. I wish I knew how to get round paying through the nose for one! I've just set up my 400W (nominal) 12v turbine & it's going great guns right now, but I still haven't sourced a dedent 12v immersion heater. If you find one at a more reasonable price - let me know, as I will you. - keith_whitehead@hotmail.co.uk