Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Pomnept-at-aol-dot-com> Hello Gary, I made a stupid mistake. I measured circum. and called it diameter. The dimensions are 8" and 16". I hope that sounds better. I will look at your sucker gap info. . Thanks for your guidance. I can't wait for sparks! Robert Hanford