Knowing about Sensor Film Kit

I am very new to this site and this is my first ever question. I want to know what is [this black material](http://www.sensorfilmkit.com/) in this sensor film kit. I am creating a weight sensor by using this very sensor kit. Now I am short of this black film. I want to purchase it now locally but do not know the composition of this material.
This material behaves as a resistance between two aluminium foil, just to inform.
If any one can help me in this.




It's called a force sensing resistor. It's basically a film of small conductive particles mixed into a non-conductive polymer matrix on top of a conductive substrate. The more force on the film, the more conductive particles can touch the layer underneath, reducing the resistance. Sensitronics owns the original patent for the technology and their [site](http://www.sensitronics.com/fsr101.htm) shows how they're constructed, though you'll probably have to dig up the patent to find out exactly what's in the force sensing layer.


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