On this site, you will find a very good picture of Reticulated Vitreous Carbon Foam. <A HREF="http://www.ergaerospace.com/literature/erg_rvc.pdf" target="_blank">http://www.ergaerospace.com/literature/erg_rvc.pdf</A> This is the most important part of PWTC Battery. The use of RVC was NOT suggested by Alvin Snaper, the idea come from BCRI. It solved the problems of weight and rigidity and strength.