Pair of Low-cost, high output sealed Thermoelectric Peltier elements measuring 30mm x 30mm, Ideal for use in Diy & Commercial Wood Stove Fans, a must have if your building your own wood stove fan, how it works - when sandwiched between two metal heatsinks and the bottom heatsink is heated the peltier element will give out an electrical charge,this electrical charge can be used to power a small low inertia motor,by mounting the low inertia motor on the top of the largest heatsink and adding a fan blade the fan will spin and help keep a temperature differential when the bottom heatsink is heated on the stove surface,the temperature differential between both the heatsinks will allow the peltier to emit an electrical charge to the motor which will then start spinning the fan blade,the peltier will continue to emit an electrical charge powering the motor until the heat source is removed,this is basically what a wood burning stove fan is, two heatsinks,a peltier element,a small low inertia fan and of course a fan blade, construction is fairly straightforward,as long as you mount the peltier between two heatsinks(I found using a 1cm heatsink for the bottom one (hottest)and a 5cm one for the top one worked best for me,I used a socket 7 cpu heatsink for the bottom and a socket 370 cpu heatsink for the top) and the fan on the top heatsink it should all work well once the stove gets hot,I wouldnt advise placing the peltier element directly against the stove though without using a heatsink,yes,it will get going much quicker from cold but it will probably burn out very quickly or at least the wiring will if it touches the hot stove surface,a plastic fan blade should be fine but do make sure the fan cannot fall over at all as this will cause a fire hazard if the stove top touches it at all,also make sure the blade is firmly pushed onto the motor spindle too as you dont want it spinning off when its going full pelt and ending up down the back of the stove,that would not be good! Incidentally I have used a plastic fan on the woodburning stove fan I built for the last year without any problems, it works pretty well as its lightweight, you just need to be careful and use a bit of common sense to make sure its not too close to the stove surface ! All other parts except heatsinks ie fan blades and low inertia motors are available in my ebay store,further information on these peltier elements is as follows: Peltier elements are thermo-electric heating and cooling devices that feature solid state,reliable temperature control, Popular Uses include cooling elements for mini fridges,dehumidifiers and cooling hot running ICs and Cpus such as those used in Computers,basically when connected to a DC power supply they will pump heat from one side of the element to the other meaning one side will get very hot whilst the other side will get very cold,by adding a heatsink and fan to the hot side (a necessity) to dissipate the heat the cool side will remain very very cold,varying voltages from 5v to 15v can be used,Manufacturers technical specifications are as follows,Max Watts 58,Max Temperature Differential 75 degrees C,Max Amps 3.9,Max Volts 15vdc. Peltier elements can also be used to generate free electricity simply by heating one surface and cooling the other, With a sufficient temperature differential a cell will output up to around 1 Amp at 5V ,more than enough to charge small batteries or drive a small electric motor,these things literally have hundreds of different uses and are great for experimenting with,Free p&p within the UK,international rates are below, thanks for looking ! Please Note,the peltiers on offer are moisture sealed around the edges to prevent any corrosion over time